Teachers sent out by John were rejected in one of the churches in the province of Asia, by leader Diotrephes. John wrote to command Gaius for supporting the teachers and, indirectly to warn Diotrephes.
For Gaius, hospitality was a habit, and his reputation for friendship and generosity, especially to travelling teachers and missionaries was known. To affirm and thank him for his Christian life-style, and to encourage him in his faith, John encouraged Gaius. To practice hospitality, cling to the truth, and do what is right. In contrast, Diotrephes the self-proclaimed church leader did not reflect God’s values.