There is greater evidence of the second letter being genuine than the first one. 2 Thessalonians is quoted by almost all the early church fathers and writers. Clement of Alexandria, Tertullian, Justin Martyr, Iraneaus and Polycarp are among these early writers who quote from this work of Paul.
Arguments for Paul’s Authorship
1. Paul identifies himself as the author twice in the book (1:1; 3:17).
2. The thoughts are Paul’s beyond doubt.
3. The vocabulary, style and teachings are typical Paul.
Arguments against Paul’s authorship
1. Eschatology. It is claimed that this book teaches a different view of the end of the world and the second coming that does the first letter. Much is made of the two Greek words (parousia and epiphenia) used to describe the second coming of Christ.
2. Change of Audience. Some attempt is made to say that the first letter is addressed to Gentiles and this one to those with a Jewish background. There is nothing in this letter that a gentile could not understand. Paul had spoken about these things (2:5).
3. Change of tone and style. It is noted that the first letter is filled with exhortation and encouragement. (1:2; 2:3) The second letter is filled with commands. (3:6, 12)
4. The Similarities. Some critics ask why the two letters are written in the same time period and on the same subject. This objection fails to consider the situation in Thessalonica at the time of the writing.
Occasion for 2 Thessalonians
This letter has 2 purposes:
1. Paul wanted to encourage them to grow in their faith (1:3) and to endure persecution (1:4).
2. Tensions were connected with the anticipation of the second coming (2:2) and some who were busybodies, lazy, not working and living disorderly (3:10-12).
Place and Date of Writing
Paul, Silas and Timothy were still together when this letter was written. After the work in Corinth (Acts 18) there is no other reference to Silas in the book of Acts. There is no evidence that all three were together after Corinth.
It is not possible for a long time to have passed since the first letter. The first letter is dated in the spring of 51 AD and this letter is written a few months later in the same year.
The teaching in 2 Thessalonians
God. There is a similar emphasis on God in both letters. Give
thanks to God (1:3; 2:13); He is the source of peace, grace and love (1:2, 12;
3:5); He is the source of comfort and hope (2:16,17); He is the author of
salvation (2:13); He counts them as worthy (1:11); and He is their judge (1:5).
Christ. Christ is described with the term “Lord” 12 times in this
short letter. He is included in the prayer for strength and comfort (2:16, 17)
and He will render vengeance upon those who do not obey him (1:7, 8).
Holy Spirit. The Holy Spirit is mentioned one time (2:13).
Ethical and Moral Teaching. Brotherly love should continue (1:3);
they should grow in faith (1:3); they are to be obedient to the teachings of
Paul (2:15; 3:4) and they should be careful to avoid being deceived (2:2, 3).
Paul also deals with the busybody and unruly who need correction and discipline
(3:6, 14, 15).
5. The Second Coming. This is the primary topic and reason for writing this letter so soon following the first one. Some were saying the Lord had already come. Others were expecting the return of Christ at any moment. Paul had to tell them that there are certain things that much take place first. (2:1-12)
6. Paul. Paul reminds them of his oral teachings [traditions] (2:5) and urges them to be obedient to all teachings. He urges them to look to the future when they will be together in God’s presence.
1. Salutation 1:1-2
2. Encouragement in Persecution 1:3-12
a. Thanksgiving 1:3-4
b. Judgment at Christ’s coming 1:5-12
i. Encouragement in troubles 1:5-10
ii. Prayer for God’s blessings 1:11-12
3. Explanation of the Day of the Lord 2:1-17
a. The Day is not already present 2:1-2
b. Events preceding the Day of the Lord 2:3-12
i. First, the rebellion 2:3
ii. The man of lawlessness 2:4-5
iii. The restrainer taken away 2:6-7
iv. The man of lawlessness 2:8-12
c. Thanksgiving and Admonition 2:13-15
d. Prayer for the readers 2:16-17
4. Exhortation to the church 3:1-18
a. Request for prayers 3:1-2
b. Expression of confidence in the Lord 3:3-5
c. Working with the disorderly 3:6-16
i. No tolerance for disorderly 3:6
ii. Example of the authors 3:7-9
iii. No work, no food 3:10
iv. Appeal to the disorderly 3:11-13
v. Stern treatment for disorderly 3:14-15
d. Conclusion 3:16-18
i. Prayer of readers 3:16
ii. Sign of authenticity 3:17-18
1 Paul, Silvanus, and Timothy, To the church of the Thessalonians in God our Father and the Lord Jesus Christ:
Paul is the author. Timothy and Silas are with Paul and “join” him in sending greetings. This opening verse is similar to the first letter.
2 Grace to you and peace from God our Father and the Lord Jesus Christ.
“Grace and peace” is a common greeting in Paul’s letters. (Rom. 1:7; 1 Cor. 1:3; 2 Cor.1:2; Gal. 1:3; Eph. 1:2; Phil. 1:2; Col. 1:2; Titus 1:4) Both verses one and two combine “God our Father and the Lord Jesus Christ.”
3 We are bound to thank God always for you, brethren, as it is fitting, because your faith grows exceedingly, and the love of every one of you all abounds toward each other,
Paul often begins his letters by expressing gratitude for the faith of those to whom the epistle is addressed. Their faith was growing exceedingly. They showed love for each other.
4 so that we ourselves boast of you among the churches of God for your patience and faith in all your persecutions and tribulations that you endure,
Paul rejoices in their patience and faith in the face of persecution and afflictions. They have learned to endure. (1 Thess. 2:14)
Paul was telling other congregations about the church, the patience, the faith and the persecution going on at Thessalonica.
5 which is manifest evidence of the righteous judgment of God, that you may be counted worthy of the kingdom of God, for which you also suffer;
Manifest evidence indicates proof to the readers that they were able to endure. Think of a seal on a legal document. Their endurance was the proof.
They were “fit” or “suited” for the kingdom of God. Their suffering is brought about because of their loyalty to the kingdom.
6 since it is a righteous thing with God to repay with tribulation those who trouble you,
God is righteous and will judge all men righteously. “To repay” means God will pay back with a full and complete payment.
God is a God of mercy and love. He is also a God of justice and wrath. (Rom. 11:22; Gal. 6:7)
7 and to give you who are troubled rest with us when the Lord Jesus is revealed from heaven with His mighty angels,
“Paying back” is not limited to punishment of the wicked. It also includes a reward for those who have suffered affliction. There will come a time when those who suffer affliction can rest, relax, and find relief from the affliction.
The rest will come at the “revelation” of Jesus, when he comes from heaven. He will bring flaming fire and the angels of God to render the wrath of God.
8 in flaming fire taking vengeance on those who do not know God, and on those who do not obey the gospel of our Lord Jesus Christ.
Vengeance belongs to God, not man. Daniel 7:13-14 teaches that Jesus will be given a kingdom, dominion and authority to execute judgment. “Vengeance” does not indicate a vindictive spirit of retaliation, but expresses the idea of administering justice.
The vengeance is rendered upon two groups of people:  Those who are inexcusable because they refused to know God;  Those who decide they will not obey the gospel. Perhaps, the first group refers to Gentiles and the second to Jews.
“Obey the gospel” implies that there are commands involved with the good news which one must accept and obey.
9 These shall be punished with everlasting destruction from the presence of the Lord and from the glory of His power,
Both groups mentioned above will suffer punishment. The word “punishment” is from a Greek word for the legal term for the result of a law suit. We would call it “punitive damages.”
The punishment comes from an unbiased judge. The punishment is described as:  Eternal;  Destruction;  Separation from God;  Exclusion from any blessing or reward.
Some of the punishment in hell is the awareness of being banished from the Lord’s presence. Remember, there is no punishment if one is not conscious of it or has no memory of their life on earth.
10 when He comes, in that Day, to be glorified in His saints and to be admired among all those who believe, because our testimony among you was believed.
This verse shows both the certainty of Christ’s coming and the uncertainty of when he will come. There is one coming, not two, three, seven or more.
The purpose of his coming is two-fold.  “To be glorified with his saints.” Christ will be glorified when all the faithful saints are gathered together in glorified bodies.  “To be marveled at.”
All will marvel (surprise mingled with admiration) at his demonstration of love, grace, power, and wisdom. All the believers will marvel in that day.
“In that day” indicates - -  The day is singular.  A day of punishment for those who know not God and those that do not obey the gospel.  A day of victory for the faithful.
11 Therefore we also pray always for you that our God would count you worthy of this calling, and fulfill all the good pleasure of His goodness and the work of faith with power,
The Greek word translated “Therefore” (NKJV) and “Wherefore” (KJV) means “to this end.” The end indicates that the second coming will be the end of time, the end of this world, the end of wickedness, the end of affliction, hardship and persecution, the end of suffering. Paul continues to pray for them to remain faithful so that the end will be a time of rejoicing and victory.
The “calling” in Thessalonians is:  A calling to salvation by believing and obeying the gospel. (2 Thess. 2:13-14);  A calling to the entrance of the eternal state. (1 Thess. 1:12; 5:24)
Paul prays that they will have the things they desire as they demonstrate the “work of faith” with power.
12 that the name of our Lord Jesus Christ may be glorified in you, and you in Him, according to the grace of our God and the Lord Jesus Christ.
The purpose of such a prayer is that the name of Jesus will be glorified. “In you” refers to their daily lives, their conduct, their desires for goodness. A genuine Christian will bring glory to him because he is recognized as Lord. (Matt. 5:16; 2 Cor. 9:13; 2 Pet. 2:9, 12)
1 Now, brethren, concerning the coming of our Lord Jesus Christ and our gathering together to Him, we ask you,
This begins a new section. This is not related to chapter one. In chapter 1, the emphasis is on the judgment and the punishment of the wicked. Chapter 2 is concerned with the coming of the “man of sin.”
The term “gathering together” is found only one other time in the NT (Heb. 10:25 “assembling of ourselves together”). Here - It refers to the gathering of the saints at the second coming of Christ. This is the same time as 1 Thess. 4:13-18.
2 not to be soon shaken in mind or troubled, either by spirit or by word or by letter, as if from us, as though the day of Christ had come.
There was some misunderstanding about the coming of Christ.
NOTE: There is a difference in “misunderstanding” and “false doctrine.” Most of the ISSUES that have divided the body of Christ have NOT been doctrine, they have been about methods, opinions, personal preferences, etc. Here the flaw was in the misapplication of Paul’s teachings.
“Shaken” is from a word meaning “to shake, to cause to move, to waiver or totter.”
Notice the word “soon”, which shows that they did not give long and proper consideration to the matter. If the message is oral or written, from Paul or another, it should not shake their faith.
Many were preaching, “The day of the Lord is at hand” - literally “is now present”. (See Rom. 8:38 “things present”; 1 Cor. 7:26 “present distress”)
NOTE: Paul denies that it is now. J. B. Lightfoot translates this “is imminent.” His note states, “The Apostle does not deny that the day of the Lord may be near. He asserts that it is not imminent.” Some were teaching that the coming had occurred in a silent and invisible way. (2 Tim. 2:17-18)
3 Let no one deceive you by any means; for that Day will not come unless the falling away comes first, and the man of sin is revealed, the son of perdition,
A strong warning is given to any who would “deceive” them whether through wicked intent or mislead into wrong thinking. Church history shows how many are quickly lead away by every new fad that comes along.
RED FLAG - MARK THIS DOWN - BE ASSURED - - - Christ will not come until there is a falling away first.
NOTE: if apostasy is impossible, Christ will never
come. The “man of sin” must be revealed. This man is so under sin that he is the
embodiment of it. The “son of perdition”, others translate “lawless one.” Both
terms fit the state of total evil, sin, lawlessness. This same term is used to
describe Judas in John 17:12.
There has been much discussion about the identity of this man of sin. Is this a specific individual - Nero? Is this an office - Pope or Emperor? Is this a teaching - (pick a false doctrine that would lead men away)? Many suggestions have been offered - Hitler, Stalin, Henry Kissinger, Nero, the Pope. None of these fits the text.
Whoever or whatever this refers to - [A] It was clear to the readers of the first century; [B] It was already at work; [C] Had already taken place by the time later books of the Bible were written. (Rev. 1:3)
4 who opposes and exalts himself above all that is called God or that is worshiped, so that he sits as God in the temple of God, showing himself that he is God.
Here is the description of this “man of sin” - -
A. He opposes God - This word means, “to be set against, adversary, to oppose.” Those who oppose God, reject his teachings, deny the Son of God could be part of what is being considered here.
B. Exalts himself - This is in the middle voice (what one does for himself) so this is not a man that others have exalted. Here is one who has literally exalted himself over God and every concept of deity.
C. Sits in the temple of God - He takes a seat, positon, authority as places himself into God’s place. The temple could refer to the church, individual Christians, or the literal temple in Jerusalem.
D. Setting himself forth as God - Literal “announcing that I myself am God.” Not that he is the God of Jesus and Christians, but that he is God, the absolute and exclusive God.
NOTE: Many try to make this a future “Anti-Christ.” Study 1 John 2:18; 22; 4:3 and 2 John 1:7 A] There are many, not just one. B] They are already in the world, not in the future. C] Denies both Father and Son. D] Deny that Jesus came in the flesh.
5 Do you not remember that when I was still with you I told you these things?
This information is not new. Paul preached about these things when he was there in person. The readers are now reminded of that teaching. The word “told” means a repetition of the teaching (as a parent says, “I have told you a 1,000 times to clean your room.”)
6 And now you know what is restraining, that he may be revealed in his own time.
Since I told you many times, and now am writing this letter, YOU KNOW!
“What is restraining” implies that something was a
restraining force. This could refer to the Jewish state, the Roman state, Paul
himself, or some other strong influence on the church (James, for example). Some
have suggested that the restrainer was the Holy Spirit, preaching of the gospel,
or God’s providence in the world.
He will be revealed in his own season. When it is the proper time. We do not know who chooses the proper time - the man of sin, God, church, world affairs. If you take the view that the restraint is God’s providence, then the proper time would be when it fits in God’s scheme for this revelation.
7 For the mystery of lawlessness is already at work; only He who now restrains will do so until He is taken out of the way.
This “mystery” was already at work. Mystery refers to that
which is concealed, hidden. This hidden, under the surface work, was now
becoming visible. Still mostly hidden, but enough was known about it to know it
was already working.
Here the restrainer is considered a person. In verse 6 “that which” is present active neuter. Here it is masculine. This passage is difficult to put into English. It does seem clear that the evil was at work and would be of a limited duration. It was not yet fully revealed.
Like the man of sin, there has been much discussion about the identity of the restrainer.
8 And then the lawless one will be revealed, whom the Lord will consume with the breath of His mouth and destroy with the brightness of His coming.
“Then” is in contrast to “now”. “Will be revealed” is used for the third time (3, 6, 8).
This lawless one = [A] Whom the Lord will slay; [B] There
is significance of the his coming.
The Lord shall slay with the breath of his mouth = He shall be destroyed by teaching of truth. (See Rev. 1:16; Heb. 4:12)
This teaching will bring to naught the appearing of this lawless one.
“Brightness” (Gk. epiphaneia) = appearing, appearance. Here it is translated “brightness.”
“Coming” (Gk. parousia) is the common term for the second
coming. This word mean to come or arrive.
Many have tried to make a distinction between these two terms. They want epiphaneia to refer to the “rapture” phase and parousia to mean the visible coming to set up the kingdom. Both of these are false.
NOTE: In this verse both words are used about the same event.
9 The coming of the lawless one is according to the working of Satan, with all power, signs, and lying wonders,
This coming is in contrast to the coming of Christ. This
coming is according to the working of Satan. He is not Satan. He is working in
harmony with Satan and in agreement with Satan.
“Signs and lying wonders” “Signs” are observable acts.
“Wonders” = something exceptional which causes wonder or marvel.
“Lying” = this power, sign, wonder is false and its purpose is to deceive.
10 and with all unrighteous deception among those who perish, because they did not receive the love of the truth, that they might be saved.
All kinds of deception will take place. Like Satan, he will
use all kinds of deception on them that perish (literally “them that are
perishing”). He wants to keep the lost, lost. Here the unbeliever is mentioned.
Satan wants to deceive Christians, also.
Satan wants to keep them lost. They do not love the truth. If they loved the truth, they would obey it and be saved. Why are they lost? Because they have chosen not to receive the truth.
11 And for this reason God will send them strong delusion, that they should believe the lie,
Because they do not love the truth, God sends them a strong delusion. (See Rom. 1:18; 2 Cor. 4:4) This is a “strong delusion” sent from God.
God always allows men to choose their own way. This is the same principle as in Romans 1:24, 26, 28. (See Is. 66:3-4)
It may well be said that the means by which one is deceived is God’s permissive agency - not God’s direct agency. God did not MAKE them believe a lie. They had already decided.
12 that they all may be condemned who did not believe the truth but had pleasure in unrighteousness.
They will be judged because the choose not to believe the truth. This shows that: [A] God is not “forcing” them to believe a lie; [B] God is just in his action. They had pleasure in rejecting the truth.
To reject truth = rejection of God, rejection of the Bible, rejection of Jesus, rejection of worship. It is the opposite of all that is truth.
13 But we are bound to give thanks to God always for you, brethren beloved by the Lord, because God from the beginning chose you for salvation through sanctification by the Spirit and belief in the truth,
Paul now returns to the matter of the brethren there. He is glad for their stand, even in the face of this rising man of sin. The word “bound” shows that this was something he just had to do.
How did they avoid believing this lie of the man of sin? Answer - They chose to believe the truth. The result is sanctification and salvation. Sanctification = set apart for God. There is a clear contrast between those who believe not the truth and those who believe the truth. The truth = God’s revelation of how men can be made righteous through Jesus Christ, that is, the gospel. (See Jude 3 “the faith”)
14 to which He called you by our gospel, for the obtaining of the glory of our Lord Jesus Christ.
Our salvation is that into which we are called. This refers to the time when we heard the gospel and believed it. When we respond and obey the gospel, we are hearing the call of God.
God still calls people in the same way today. The purpose of this calling is to obtain the glory of Jesus Christ.
15 Therefore, brethren, stand fast and hold the traditions which you were taught, whether by word or our epistle.
Because you have been called, obeyed the gospel, believed the truth, stand fast. Don’t be led astray. Don’t believe the lie of the lawless one.
In contrast, keep the traditions (oral teachings handed down) as they were taught by Paul. Some of this teaching was oral and some was in his two letters to them. Only those communications from Paul were to be accepted. Any other message must be weighed against the teachings of Paul. (See also Gal. 1:8-9)
16 Now may our Lord Jesus Christ Himself, and our God and Father, who has loved us and given us everlasting consolation and good hope by grace,
17 comfort your hearts and establish you in every good word and work.
Paul’s ends the chapter with a prayer for them. He makes
A. God loves us.
B. He gave us eternal life.
C. He gives us comfort.
D. Only God can offer us hope.
E. God will comfort our hearts.
F. We will be established in every good work and teaching.
1 Finally, brethren, pray for us, that the word of the Lord may run swiftly and be glorified, just as it is with you,
Paul is now ready to conclude this short letter.
Pray for us – Just as the Thessalonian Christians were suffering persecution, so were Paul and those with him.
Pray that the events discussed in this letter occur quickly and are over with soon.
Pray that the gospel message will travel far and fast.
Pray that Jesus will be glorified.
2 and that we may be delivered from unreasonable and wicked men; for not all have faith.
Pray that we can escape the wicked men who seek to kill Paul. Everyone has not heard. There are many that do not have faith in Christ. We have a lot of work yet to do.
3 But the Lord is faithful, who will establish you and guard you from the evil one.
Can God protect us from evil? Yes, He can. Study how God protected others in the Old Testament and in the New Testament. Providence does not require a miracle. God can use natural means to accomplish His will.
4 And we have confidence in the Lord concerning you, both that you do and will do the things we command you.
Paul is confident that they are doing, and will continue to do the things he commanded of them – both what he taught while there and what he has commanded in this letter.
5 Now may the Lord direct your hearts into the love of God and into the patience of Christ.
We pray for God to “Guide, guard and direct us.” God can direct our hearts to do the will of God. We can be directed to live with the patience of Christ.
6 But we command you, brethren, in the name of our Lord Jesus Christ, that you withdraw from every brother who walks disorderly and not according to the tradition which he received from us.
There is one final issue that must be discussed.
Some who read the first letter were so ready and anxious to see the return of Christ. They were afraid that they might be working and would miss seeing Jesus when he comes. Many were just waiting for Christ to come.
Paul tells the church that we must withdraw from brothers that are not living and working as they should.
Withdraw = This Greek word means to set in order, arrange. It is used here in the sense of “diminish, contract, shorten, cause to cease, cease to exist, to remove one’s self, withdraw one’s self, to depart, to abstain from familiar intercourse with one.” Thayer’s Greek Lexicon
“Walks disorderly” refers to one who walks out of rank. Thayer says, “deviating from the prescribed order or rule.”
“Tradition” is “a giving over which is done by word of mouth or in writing, i.e. tradition by instruction, narrative, precept, etc.” (Thayer)
NOTE: Most uses of the tradition in the NT are in a negative sense of keeping or holding a tradition as more important than the command of God. See Mark 7.
7 For you yourselves know how you ought to follow us, for we were not disorderly among you;
Paul urges them to remember and follow the example he set before them when he was there. Paul behaved himself.
8 nor did we eat anyone's bread free of charge, but worked with labor and toil night and day, that we might not be a burden to any of you,
Paul, and those with him, were not a burden to the people. They did not charge for their work. They worked night and day so they would not burden the new Christians with his support.
9 not because we do not have authority, but to make ourselves an example of how you should follow us.
It would have been OK to seek their support. There is authority for this.
Paul wanted to show them an example of how they should work.
10 For even when we were with you, we commanded you this: If anyone will not work, neither shall he eat.
Here Paul presents a principle that applies to many in the world today. There are some who are disabled and cannot work. We willingly support them. Others are just lazy, and seek to live off of others. They ask for help from the government, churches, and charitable organizations.
Paul is not suggesting that we should let people starve to death. He is saying that God intended for man to work and earn his way in life.
The Judeo-Christian Work Ethic begins in the Garden of Eden. Adam was to work and tend the garden. This was a command from God before sin entered the world.
11 For we hear that there are some who walk among you in a disorderly manner, not working at all, but are busybodies.
Now Paul addresses the charges he has heard (probably from Timothy).
Disorderly – Thayer says, “1) disorderly, out of ranks (often so of soldiers); 2) irregular, inordinate, immoderate pleasures; 3) deviating from the prescribed order or rule.”
Not working – no work, labor, doing business, constructive and productive work
Busybodies - 1) to bustle about uselessly, to busy one’s self about trifling, needless, useless matters; 1a) used apparently of a person officiously inquisitive about other’s affairs (from Thayer)
12 Now those who are such we command and exhort through our Lord Jesus Christ that they work in quietness and eat their own bread.
Is this clear enough?
Command – Paul is giving an order, a charge as an apostle of Christ
Exhort – This word means to encourage, strengthen, exhorting and comforting, to instruct, teach
Quietness – Not total silence, not absence of sound. This word means calm, peaceful, tranquil. It is the opposite of loud and boisterous. The same word is translated “silence” in 1 Timothy 2:11.
Eat their own bread – implies that they work, earn money buy bread for themselves. We should not live and eat off the work and labor of others.
13 But as for you, brethren, do not grow weary in doing good.
Paul now cautions that we should be willing to help, support and share with others. Some are not able to work – lame, blind, very sick, very old may need our help. Read Ephesians 4:28. We should work so we have the ability to give to those in need.
Don’t grow tired of doing good.
14 And if anyone does not obey our word in this epistle, note that person and do not keep company with him, that he may be ashamed.
What if some who read this letter decide to ignore the commands?
Note that person – What is involved in the command to “note that person”? Identify them. Speak to them, Teach them. Instruct them, Exhort. Admonish. This is not a public announcement with intent to shame or embarrass them.
Not keep company – Do not treat them as if all is OK in their life and they are headed for heaven. Fellowship is about what we share in common. If you treat them if a way they believe all is well with their spiritual state, they will not see the need to change or repent.
Ashamed – The goal of all church discipline is not to kick them out. The goal is to bring them back. Help them to see what they are throwing away by their actions. The goal of taking a toy away from a child to help them miss it and change their behavior to get it back.
15 Yet do not count him as an enemy, but admonish him as a brother.
He is still a brother. He is wrong and is living or teaching error. He is in danger of being lost. But he is still a brother and needs to be treated in that way.
Parents punish their children – but they still love them. The child does not become the enemy. He just did wrong and needs to change.
Admonish – warn, exhort, strongly encourage change and repentance
16 Now may the Lord of peace Himself give you peace always in every way. The Lord be with you all.
Here is the conclusion of the letter. Paul expresses the desire that God will give them peace. Peace with God. Peace with each other. Peace with their own heart and soul.
17 The salutation of Paul with my own hand, which is a sign in every epistle; so I write.
Most of Paul’s letters were written by a scribe. But often at the end he would add a note or a signature in his own hand.
See also Galatians 6:11 and 1 Corinthians 16:21
While only mentioned here and 1 Corinthians and Galatians, Paul says he does this with every epistle.
18 The grace of our Lord Jesus Christ be with you all. Amen.
Paul ends as he started with a prayer of grace and peace for them.
Amen – Thayer makes this comment – “so it is, so be it, may it be fulfilled. It was a custom, which passed over from the synagogues to the Christian assemblies, that when he who had read or discoursed, had offered up solemn prayer to God, the others responded Amen, and thus made the substance of what was uttered their own.”