Every believer in Christ is, in Paul's words, "an ambassador for Christ" (2 Corinthians 5:20) — a royal representative of heaven's King living on foreign soil. An ambassador does not speak for himself; he speaks on behalf of the one who sent him. He carries the King's message (the gospel), bears the King's authority, and maintains the King's character in a land that does not know his King. The Christian is always in the world but never of it — present as a representative, not absorbed as a resident. Ambassadorial life means homesickness for heaven and purposeful engagement with the present age.
AMBAS'SADOR, n. [Low L. ambassiator.] A minister of the highest rank employed by one prince or state at the court of another to manage the public concerns of his own prince or state, and representing the person and dignity of the sovereign he serves. Paul employs this term for ministers of the Gospel: "We are ambassadors for Christ, as though God did beseech you by us" (2 Cor. 5:20).
The modern church has largely forgotten that Christians are ambassadors, not immigrants. Immigrants assimilate — they adopt the culture, language, and values of their new home. Ambassadors do not assimilate; they represent. When the church simply mirrors the surrounding culture's morals, aesthetics, and priorities, it has abandoned its embassy. The "relevant church" movement, in trying to make the gospel palatable, often produces not ambassadors but cultural chameleons who have nothing distinctive to offer a world that already has enough of itself.
2 Corinthians 5:20 — "We are therefore Christ's ambassadors, as though God were making his appeal through us."
John 17:18 — "As you sent me into the world, I have sent them into the world."
Philippians 3:20 — "But our citizenship is in heaven. And we eagerly await a Savior from there, the Lord Jesus Christ."
1 Peter 2:11 — "Dear friends, I urge you, as foreigners and exiles, to abstain from sinful desires, which wage war against your soul."
G4243 — presbeuō (πρεσβεύω) — to be an ambassador, to act as envoy; from presbys (elder, senior); the act of representing a superior authority.
G3941 — parepidēmos (παρεπίδημος) — a stranger alongside, a temporary resident, a sojourner; the NT description of the believer's status in this world.
H6735 — tsîr (צִיר) — a messenger, envoy, ambassador; used in Proverbs 13:17 of a faithful messenger.
When a Marine veteran plants a church in a neighborhood hostile to the gospel, he is an ambassador — carrying the message of his King into enemy territory. His conduct, his family, his integrity, his generosity are all diplomatic dispatches from the Kingdom of God. The moment he adopts the priorities of the surrounding culture over the Word of his King, his embassy goes dark.