Context: 3 John, also by "the Elder" John (~90–100 AD), is a personal letter to Gaius — a specific Christian praised for his generous hospitality to itinerant missionaries. It is the positive counterpart of 2 John: where the second warns against imprudent hospitality to false teachers, the third praises faithful hospitality to servants of the gospel.

Three characters: Gaius — a faithful Christian whose "soul is prospering" just as his outer life prospers (v.2 — a text frequently misapplied to material prosperity out of context). Diotrephes — a local leader who "likes to put himself first" (v.9), refuses to receive John's missionaries, speaks evil against them with empty words, and expels from the Church those who receive them. It is one of the rare glimpses of concrete ecclesial conflict in the NT — the danger of authoritarianism that serves the ego. Demetrius — a positive counter-example commended by everyone and by truth itself.

Message: Hospitality as a missionary ministry is one of the primary ways of participating in the work of the gospel without being the preacher. "We ought to support people like these, that we may be fellow workers for the truth" (v.8) — Christian mission is always collaborative. "Do not imitate evil but imitate good. Whoever does good is from God" (v.11).