The theme of this epistle is the importance of maintaining fellowship and undergirding the ministries of people who have committed their lives to sharing the message of new life in Christ. John wrote this brief letter to commend Gaius as a fellow worker in the truth because of his hospitality and support of missionaries who had been sent, evidently by John, to teach and equip believers in the churches in the region of Asia Minor. At the same time, this letter rebukes the pride and misconduct of Diotrephes in his rejection of those who teach the truth. John also commends Demetrius (who may have delivered this letter) to the church and informs Gaius of his plan to visit the church and settle the difficulties. The apostle starkly contrasts a man who wants others to look to him and another man who wants others to look to Jesus. One is the embodiment of selfishness and the other of servanthood.
From Handbook to Scripture
"Teach us to number our days, that we may gain a heart of wisdom."