Commendation of Gaius. John expresses his delight at the witness borne to the moral integrity of Gaius by some who had visited the apostle. He prays that Gaius may have prosperity and health commensurate with his spiritual wellbeing. Gaius is also commended for the hospitality which he is known to give to evangelists who travelled in the interests of the Gospel. To entertain such men and set them on their way in a worthy fashion was gracious service to the truth.
3 John 1:3. brethren: possibly the visitors who reported to the elder the facts named in 2 John 1:4.
3 John 1:5. brethren and strangers: these would be Christians compelled, for some reason, to travel, and especially itinerant evangelists, who went forth from some Christian community to visit other churches and to break up new ground (see Introduction). Such Christians usually received hospitality from brother Christians, the public inns, because of their low moral tone, being undesirable halting-places for Christian travellers and evangelists (p. 615).
3 John 1:6. the church: i.e. that to which the writer belonged.
3 John 1:7. the Name: i.e. that of Christ (cf. Acts 5:40 f.). They went forth out of love for Christ and zeal for the Gospel. For that reason, and to avoid contact with idolatry, they were unwilling to accept the hospitality sometimes offered them in heathen homes.