For I was overjoyed when the brothers came and testified about your devotion to the truth, in which you continue to walk.
I. John receives a good report of Gaius's faith and charity from the brethren. Gaius’s love for the brethren and hospitality to strangers proves his sincerity in the faith. II. Gaius is commended for his hospitality, a virtue extended to strangers and those of different churches. III. John expresses great joy in hearing of Gaius's walk in truth.
Commenting on 3 John 1:3-8
For I rejoiced greatly when the brethren came,.... From the place where Gaius lived, to that where John now resided; these brethren seem to be preachers of the word, who travelled from place to place to spread the Gospel: and testified of the truth that is in thee; either of Christ, who was formed in him; or of the Gospel, which had a place in...
Verse 3. For I rejoiced greatly when the brethren came. Who these were is not certainly known. They may have been members of the same church with Gaius, who, for some reason, had visited the writer of this epistle; or they may have been the "brethren" who had gone from him with a letter of commendation to the church, (,) and had been rejected by...