3John 1:1-4 The elder unto the well-beloved Gaius, whom I love in the truth. Beloved, I wish above all things that thou may prosper and be in health, even as thy soul prospers. For I rejoiced greatly, when the brethren came and testified of the truth that is in thee, even as thou walks in the truth. I have no greater joy than to hear that my children walk in truth.
‘Elder’ John was an elder in three ways: By title, being an apostle and a preaching elder; by seniority, both as a Christian and as an apostle. He is thought to have been the oldest of the apostles, to have had the most years of Christian experience and to have been the only one to die a natural death; by age, being about 90 years old at this writing.
‘Unto the well-beloved Gaius’ the second epistle of John to an individual (2Jn. 1:1). ‘Gaius’ it is not known whether this Gaius was the same mentioned in Acts 19:29; 20:4; Romans 16:23 and 1Corinthians 1:14, or not.
‘I wish above all things that thou may prosper and be in health, even as thy soul prospers’ when the soul prospers, that part which is the seat of the desires, feelings, passions, appetites, and emotions, one stays in health. The soul reflects whether or not the thoughts (originating from man’s spirit) have been captured to the obedience of Christ, or not (2Cor. 10:3-5; Jas. 1:13-16).
Three kinds of blessing that are God’s will: Material prosperity (3Jn. 1:2; Jos. 1:5-9; 1Sam. 2:7-8; 1Kin. 2:3-4; 1Chron. 29:12; Ezr. 8:22; Job 36:11; Ps. 1:1-3; Matt. 7:7-11; 17:20; 21:22; Mark 9:23; 11:22-24; John 15:7, 15:16; 2Cor. 9:6-8; Php. 4:19). Physical healing and health (3Jn. 1:2; Ex. 15:26; Ps. 91:1-16; 103:3; Isa. 53:4-5; 58:8; Matt. 8:17; 1Pet. 2:24; Jas. 5:14). Soul salvation (3Jn. 1:2; Matt. 1:21; Rom. 1:16; 10:9-10; Eph. 1:7; 2:8-9; Heb. 7:25; 1Jn. 1:7, 9; Rev. 1:5).
If such blessings are the will of God for one man, they are for all men alike who will have faith for them, because there is no partiality in the gospel.
‘I have no greater joy’ John found joy in the one great thing of life, the greatest, in the testimony of those who have chosen eternal life. There is no greater joy.
‘Children walk in truth’ from this we gather that Gaius was a convert of John the apostle. Or, it could refer to Christians under John’s care, those who were his juniors in Christ and in age.