" Search their ways and principles to the bottom, and you will find that it had no other root but this mistake, namely, that attempting rigid mortification, they fell upon the natural man instead of the corrupt old man, — upon the body wherein we live instead of the body of death. Neither will the natural Popery that is in others do it. Men are galled with the guilt of a sin that hath prevailed over them; they instantly promise to themselves and God that they will do so no more; they watch over themselves, and pray for a season, until this heat waxes cold, and the sense of sin is worn off: and so mortification goes also, and sin returns to its former dominion. "

― John Owen , Mortification of Sin