International Standard Bible Encyclopedia
(1) Greek ginomai, used in New Testament for a change of state, corresponding to Hebrew hayah of Old Testament. Compare Matthew 18:3 with Deuteronomy 27:9.
(2) For what is fitting, suitable, proper, in New Testament: "prepei" (Matthew 3:15 Ephesians 5:3 1 Timothy 2:10); in Old Testament, na'awah, na'ah, Psalm 93:5: "Holiness becometh thy house." in this sense, the adverb "becomingly" must be interpreted: "Walk becomingly toward them that are without" (1 Thessalonians 4:12), i.e. in a way that is consistent with your profession.