In Scripture, an alien is a foreigner residing among God's people — not a citizen by birth, yet granted protected status under Mosaic law. The Law commanded Israel to love the alien: "You shall not wrong a sojourner or oppress him, for you were sojourners in the land of Egypt" (Exod 22:21). Theologically, believers are themselves described as aliens in this world — citizens of heaven temporarily dwelling on earth (1 Pet 2:11; Phil 3:20). This dual meaning reveals a profound spiritual truth: God's people are resident aliens in the present age, belonging ultimately to another country.
ALIEN, n. A foreigner; one born in, or belonging to, another country; one who is not a citizen of the country in which he resides. An alien is a person born of parents who are not citizens of the country where he is born, or naturalized in it.
adj. Foreign; not belonging to the same country, land, or government. Estranged; adverse to; not belonging to a person; as, principles alien to his character.
Modern usage has entirely secularized alien into a purely political and legal category — and more recently into science fiction imagery (extraterrestrial beings). This strips the word of its deep biblical resonance. Scripture's alien is not a political problem to be managed but a neighbor to be protected and loved (Lev 19:34). Equally lost is the believer's self-understanding as an alien in the world — producing not withdrawal but holy non-conformity. The church that loses sight of its own alien status becomes indistinguishable from the culture it was sent to transform.
PIE *al- ("beyond, other")
→ Latin alius ("other, another")
→ Latin alienus ("belonging to another, foreign")
→ Old French alien → English "alien"
Hebrew:
גֵּר (ger, H1616) — sojourner, alien, temporary resident
→ גּוּר (gur) — to sojourn, dwell as a stranger
Greek:
ξένος (xenos, G3581) — stranger, foreigner, guest
πάροικος (paroikos, G3941) — alien resident (para- + oikos "house")
ἀλλότριος (allotrios, G245) — belonging to another, foreign
• Exodus 22:21 — "You shall not wrong a sojourner or oppress him, for you were sojourners in the land of Egypt."
• Leviticus 19:34 — "You shall love him as yourself, for you were aliens in the land of Egypt."
• 1 Peter 2:11 — "I urge you as aliens and strangers in the world, to abstain from sinful desires."
• Philippians 3:20 — "But our citizenship is in heaven."
• Hebrews 11:13 — "They admitted that they were aliens and strangers on earth."