Repudiation of faith in God, found in both the OT and NT. Israel is accused by Jeremiah of apostasy (Jer. 2: 19) and apostates are said (Heb. 6: 6) to crucify again the Son of God. Paul says that the day of the Lord will not come unless the ‘apostasy’ (‘rebellion’, NRSV; ‘final rebellion’, REB; ‘Great Revolt’, NJB) comes first (2 Thess. 2: 3).