:
1 The elder unto the wellbeloved Gaius, whom I love in the truth. 2 Beloved, I wish above all things that thou mayest prosper and be in health, even as thy soul prospereth. 3 For I rejoiced greatly, when the brethren came and testified of the truth that is in thee, even as thou walkest in the truth. 4 I have no greater joy than to hear that my children walk in truth. 5 Beloved, thou doest faithfully whatsoever thou doest to the brethren, and to strangers; 6 Which have borne witness of thy charity before the church: whom if thou bring forward on their journey after a godly sort, thou shalt do well: 7 Because that for his name's sake they went forth, taking nothing of the Gentiles. 8 We therefore ought to receive such, that we might be fellowhelpers to the truth. 9 I wrote unto the church: but Diotrephes, who loveth to have the preeminence among them, receiveth us not. 10 Wherefore, if I come, I will remember his deeds which he doeth, prating against us with malicious words: and not content therewith, neither doth he himself receive the brethren, and forbiddeth them that would, and casteth them out of the church. 11 Beloved, follow not that which is evil, but that which is good. He that doeth good is of God: but he that doeth evil hath not seen God. 12 Demetrius hath good report of all men, and of the truth itself: yea, and we also bear record; and ye know that our record is true. 13 I had many things to write, but I will not with ink and pen write unto thee: 14 But I trust I shall shortly see thee, and we shall speak face to face. Peace be to thee. Our friends salute thee. Greet the friends by name.
[AD 614] Andreas of Caesarea on 3 John 1:1
John writes this letter to encourage some fellow believers. He writes to Gaius and testifies to his great hospitality, which he praises. He says that someone who does such good is from God. He goes on to tell him to expel Diotrephes, who has not learned to do the same thing. He also praises Demetrius for doing the same as Gaius and mentions his faith as a testimony to his virtue. His main purpose for writing is the same as it was in his second letter.

[AD 735] Bede on 3 John 1:1
The elder to the beloved Gaius, etc. Who and what kind of person this Gaius was, is revealed in the course of the Epistle. Because clearly he accumulated good deeds in addition to the faith in Christ which he had received, and although he was not sufficient for preaching the word himself, he rejoiced to sustain those who did preach with his resources. We believe this Gaius to be the one whom Paul mentions in the Epistle to the Romans, saying: “Gaius, my host and the host of the whole church, greets you” (Rom. XVI). For he was accustomed to be called a host both as one who receives and is received, he was the host of the entire church because he kindly received all who came to him, namely both the preachers and the hearers of the word, as the following parts of this Epistle clearly declare. Hence, John also loves him in the truth, that is, he appears to love him only with the view of eternal goods, not for the sake of temporal benefits. But it seems that Gaius was in Corinth, from the fact that Paul, having stayed in that city, wrote the Epistle to the Romans, whom he greets in his name. And also in the Epistle to the Corinthians, he mentions Gaius as a citizen of Corinth, saying: “I thank my God that I baptized none of you except Crispus and Gaius, lest anyone should say that you were baptized in my name” (I Cor. I).

[AD 990] Oecumenius on 3 John 1:1
The person who loves God with heartfelt charity loves in the truth, a point which John often makes in his other letters.

[AD 1781] Richard Challoner on 3 John 1:1
St. John praises Gaius for his walking in truth and for his charity, complains of the bad conduct of Diotrephes and gives a good testimony to Demetrius.
[AD 449] Hilary of Arles on 3 John 1:2
Things are going well for Gaius because his soul is carrying on in good works as the will of his mind directs him.

[AD 735] Bede on 3 John 1:2
Beloved, I pray that in all things, etc. He says, I frequent prayers to the Lord, that you may complete well what you do well. And just as now your soul, that is, the internal intention of your mind prospers, that is, advances in abundant works of alms, and the liberality of a bountiful mind, and the resources of money which you share with the needy, so may you always be able to lead a life full of virtues with the Lord’s help.

[AD 990] Oecumenius on 3 John 1:2
Gaius is doing well, says John, because he is living according to the truth of the gospel.

[AD 449] Hilary of Arles on 3 John 1:3
The truth of Gaius’s life was seen in the perfection of his works. He was a man who went about without any guile in thought, word or deed. Instead of that, he followed the commandments of God to the best of his ability.

[AD 990] Oecumenius on 3 John 1:3
Gaius is walking in the truth because he is following the gospel in all its pure simplicity. To walk does not mean to put one foot in front of the other but to make orderly spiritual progress within the limits of what the soul is able to bear. This is something which very few people manage to achieve.

[AD 735] Bede on 3 John 1:4
I have no greater joy than this, etc. That is, that I recognize those whom I have begotten to God by preaching or baptizing, observing the truth both of right faith and good operation.

[AD 1781] Richard Challoner on 3 John 1:4
No greater grace: that is nothing that gives me greater joy and satisfaction.
[AD 735] Bede on 3 John 1:5
Beloved, you act faithfully in whatever you work for the brethren, etc. You act faithfully, he says, as if he said: Just as you are truly faithful, so you act, showing your faith by your works.

[AD 449] Hilary of Arles on 3 John 1:6
Visitors praised Gaius to the rest of the church because of his generous hospitality to those who were in God’s service.

[AD 449] Hilary of Arles on 3 John 1:7
This means that the servants of God have accepted no assistance from those who are not believers.

[AD 735] Bede on 3 John 1:7
For they went out for the sake of the name, accepting nothing from the Gentiles. When it says for the name, it is to be understood as of the Lord Jesus Christ. For the ancients spoke in this manner. And for two reasons, they went out for the name of the Lord, either to preach, evidently coming of their own accord in the name of Him, or because of the faith and confession of the holy name, they were expelled from their homeland by their fellow citizens or relatives.

[AD 1781] Richard Challoner on 3 John 1:7
Taking nothing of the Gentiles: These ministers of the gospel are commended by St. John, who took nothing from the Gentiles, lest they should seem to preach in order to get money by it.
[AD 604] Gregory the Dialogist on 3 John 1:8
Whoever gives practical assistance to those who have spiritual gifts becomes a coworker with those people in their spiritual work. There are relatively few people who are spiritually gifted but many who are rich in the things of this world, and when the latter comfort poor saints with their wealth they gain a share in their spiritual riches.

[AD 614] Andreas of Caesarea on 3 John 1:8
John teaches us that we should not wait for such needy people to come to us but should rather go out and look for them, for that is what Lot and Abraham did.

[AD 735] Bede on 3 John 1:8
Therefore, we ought to support such men, etc. The blessed John, who had left all things for Christ, aligns himself with the person of believing rich men, so that he might make them more eager to have compassion on the poor and strangers: nor should it be doubted that he could have truly said what we read Paul to have said: "You yourselves know that these hands ministered to my necessities and to those who were with me. In all things I have shown you that by so laboring you must help the weak, and remember the words of the Lord Jesus, how he said: It is more blessed to give than to receive" (Acts 20). But he calls them co-workers of the truth, because he who provides temporal support to those who have spiritual gifts, becomes a co-worker in those spiritual gifts themselves. For since there are few who have received spiritual gifts, and many who are rich in temporal things, by this the rich incorporate themselves into the virtues of the poor, while they share their riches with these holy poor. Hence the Lord also says: "Whoever receives a prophet in the name of a prophet shall receive a prophet’s reward; and whoever receives a righteous man in the name of a righteous man shall receive a righteous man’s reward” (Matthew 10).

[AD 449] Hilary of Arles on 3 John 1:9
This verse teaches us that we ought to bear the abuse of those who insult us with equanimity, but sometimes we have to protest it because if we do not do so, these people will corrupt the minds of those who might otherwise have heard something good about us.

[AD 735] Bede on 3 John 1:9
I would have written to the church, but he who loves to have the preeminence among them, etc. Diotrephes, it seems, was an arch-heretic of that time, someone proud and insolent, preferring to usurp the preeminence of knowledge by teaching new doctrines, rather than humbly listening to the commands of the ancient holy Church, which John preached. Hence, aptly, Diotrephes is humorously derided, or interpreted as "mad elegance," to signify with his name even the perfidy of his heart.

[AD 1781] Richard Challoner on 3 John 1:9
Diotrephes, who loveth: This man seemeth to be in power, but not a friend to the faithful; therefore this part of the letter might be an admonition to him from the apostle.
[AD 735] Bede on 3 John 1:10
For this reason, if I come, I will bring up his deeds. That is, by openly reproving, I will bring his works to the knowledge of all. Just like the apostle Paul said: "What do you desire? Shall I come to you with a rod?"

[AD 735] Bede on 3 John 1:10
He acts, talking against us with malicious words. It should be noted that we should not arouse the tongues of detractors by our fault, lest they perish, but we should equally bear those that are incited by their own malice, so that merit may increase for us; sometimes, however, we should also curb them, lest while they disseminate evil about us, they corrupt the hearts of the innocent who could have heard good things. Hence John reproved the tongue of his detractor, lest those who could have listened might not hear his preaching and remain in their wrong ways.

[AD 990] Oecumenius on 3 John 1:10
If the principle of the gospel is that we should not return evil for evil, what is the meaning of this warning? I think that the answer is that we are not to return evil for evil when the injury has been done to us personally and to no one else. But when it affects others, we must heed what Paul says to Elymas, who was corrupting the ways of the Lord: “You son of the devil.”

[AD 220] Tertullian on 3 John 1:11
And if I glance around at their examples-(examples) of some David heaping up marriages for himself even through sanguinary means, of some Solomon rich in wives as well as in other riches-you are bidden to "follow the better things; " and you have withal Joseph but once wedded, and on this score I venture to say better than his father; you have Moses, the intimate eye-witness of God; you have Aaron the chief priest.

[AD 398] Didymus the Blind on 3 John 1:11
Light has nothing in common with darkness, and there is no agreement between Christ and Belial. The person who does good has Christ, the true light, and not darkness or Belial. But the person who does evil is from Belial and darkness and has not seen God or had any knowledge of him.

[AD 735] Bede on 3 John 1:11
Beloved, do not imitate what is evil, but what is good. He reveals that he desires him to imitate what is good by adding:

[AD 449] Hilary of Arles on 3 John 1:12
Demetrius was highly regarded by everybody because of his virtue. Some people take this verse to mean that he was criticized by everyone, but I cannot see how such an interpretation is possible.

[AD 614] Andreas of Caesarea on 3 John 1:12
In my opinion this Demetrius is the same man who made silver idols of Artemis and who once led a riot against the apostle Paul.

[AD 735] Bede on 3 John 1:12
Demetrius has received a good testimony from everyone. That is, he himself welcomed the weak and supported the needy for the sake of the truth. Therefore, Gaius should also imitate him, so that he too may be worthy of the praise of all.

[AD 990] Oecumenius on 3 John 1:12
By “all” John means primarily all those who respect the truth, though it is possible that the term should be extended to cover unbelievers as well, since Paul tried to please both Jews and Gentiles. By “the truth itself” he means the fact that Demetrius practices what he preaches. For there are some who sound good when they talk, but their subsequent actions do not live up to what they claim.

[AD 449] Hilary of Arles on 3 John 1:14
John means by this that he still has many commands to give them.

[AD 990] Oecumenius on 3 John 1:14
This is just the same as what John said at the end of his previous letter, and there is no point repeating the remarks which I made there.

[AD 215] Clement of Alexandria on 3 John 1:15
Do not let quarrelsomeness with its love of empty victory creep into our midst, for our aim is the elimination of all discord. Surely this is the meaning of the expression “Peace be to you.”

[AD 735] Bede on 3 John 1:15
Peace to you. The friends greet you, etc. He sends greetings of peace and health to friends, showing by this that Diotrephes and other enemies of the truth are foreign to your peace and salvation.