Date: Around A.D. 85-95
Purpose: To commend Gaius for showing hospitality to genuine Christian teachers.
Note: 3 John is the shortest New Testament epistle in the original Greek.
• Gaius — encouraged and affirmed
1 The elder, To my dear friend [see also vv. 2,5,11] Gaius [a common name in the Roman empire; held position of responsibility in the local church], whom I love in the truth [the truth of Christ].
2 Dear friend [Gaius], I pray that you may enjoy good health and that all may go well with you, even as [just as; prayer that outward health and prosperity correspond to inward prosperity and health of soul] your soul is getting along well.
3 It gave me great [exceeding] joy to have some brothers [other believers took note of the good example set by Gaius] come and tell about your faithfulness to the truth and how you continue to walk [to conduct one’s life] in the truth [Ps. 1:2; 1 Thess. 2:13].
Note: What do others report about us and about our walk?
4 I have no greater joy than to hear that my children [converts to the faith; may indicate that Gaius had been led to faith in Christ by John] are walking [continually and habitually] in the truth.
5 Dear friend [Gaius], you are faithful in what you are doing [Gaius’ service was really a service to Jesus Christ (cf. Matt. 10:40; 25:34-40)] for the brothers [traveling ministers or missionaries; sincere ministers of the gospel as opposed to the false teachers of 2 John; read 1 Cor. 16:6; Titus 3:13], even though they are strangers [same as “brothers” in the first part of this verse; cf. Heb. 13:2] to you.
Note: Do you open your heart and home and hand to God’s servants?
6 They [the “strangers” of v. 5] have told the church about your love [Gr. agape]. You will do well [please; a polite request] to send them on their way [to assist them on their journey] in a manner [supply them with food, finances, and other necessities for their journey] worthy of [honors] God.
7 It was for the sake of the Name [indicates they were missionaries] that they went out [from the church into the world to preach the gospel], receiving no help [compensation] from the pagans [heathen; the unsaved].
8 We ought [to be morally obligated] therefore to show hospitality [to welcome, to support, to aid them as they go on their way] to such men [itinerant ministers or missionaries] so that we may work together [Gaius helped extend the work of the kingdom through his acts of gracious hospitality] for [on behalf of] the truth.
• Diotrephes — criticized and confronted
9 I wrote to the church, but Diotrephes, who loves [a constant attitude] to be first [to be the leader; had an inflated opinion of himself; probably one reason why he did not show hospitality to traveling teachers; cf. Matt. 23:6], will have nothing to do with us [Diotrephes refused to submit to authority; he refused to have fellowship with John, one of the Lord’s own apostles].
10 So if I come, I will call attention [possibly means that he would discipline Diotrephes] to what he is doing, gossiping maliciously [talking nonsense; making false and empty charges] about us. Not satisfied with that, he refuses to welcome the brothers [traveling missionaries]. He also stops those [like Gaius] who want to do so [to show hospitality] and puts them out of the church [Diotrephes liked being in control; he was a church dictator].
11 Dear friend [Gaius], do not imitate [mimic; cf. Phil. 3:17] what is evil but what is good. Anyone who does what is good is from God. Anyone who does what is evil has not seen God.
• Demetrius — praised and commended
12 Demetrius [some believe he delivered John’s letter to Gaius or that he was a traveling missionary; note threefold tribute about Demetrius]  is well spoken of by everyone—  and even by the truth itself [Demetrius, like Gaius, walked in the truth of God’s Word].  We also speak well of him, and you know that our testimony is true.
13 I have much to write you [Gaius], but I do not want to do so with pen and ink.
14 I hope to see you soon, and we will talk face to face. Peace to you. The friends [fellow Christians] here send their greetings. Greet [personally do so] the friends [Paul had many friends] there by name.