2 Thessalonians 2:3

Let no one deceive or beguile you in any way, for that day will not come except the apostasy comes first [unless the predicted great falling away of those who have professed to be Christians has come], and the man of lawlessness (sin) is revealed, who is the son of doom (of perdition), [Dan. 7:25; 8:25; I Tim. 4:1.]