1 elder. The writer obviously is the Apostle John, presumably writing from Ephesus to a close friend in one of the nearby churches of Asia Minor. Compare the salutation in II John 1.

1 wellbeloved. Gaius is called “beloved” by John no less than four times in this short epistle (III John 1,2,5,11). He had evidently been won to Christ by John (III John 4), and John had frequently received good reports from traveling Bible teachers and others concerning his spiritual growth and godly life (III John 3).