2 Thessalonians 2:1-3

1Now we beseech you, brethren, by the coming of our Lord Jesus Christ, and by our gathering together to him,1 2That ye be not soon shaken in mind, or be troubled, neither by spirit, nor by word, nor by letter as from us, as that the day of Christ has come.

3Let no man deceive you by any means: forthat day shall not come, except there come a falling away first, and that man of sin be revealed, the son of perdition;