Let no one deceive you in any way. For it will not be, unless the departure comes first, and the man of sin is revealed, the son of destruction,
for that day shall not come, except there come a falling away first: "That day" refers to the coming of Christ that is being addressed in this book. The return of Jesus Christ is not going to happen until "there come a falling away." This phrase "falling away" (apostasia) indicates "a defection (or) apostasy" (Thayer 67-11-646). The King James Version of the Bible translates "a" falling away, but the Greek text renders "the" falling away.