Owen on sin

"Sin aims always at the utmost: every time it rises up to tempt or entice, might it have its own course, it would go out to the utmost sin of that kind. Every unclean thought or glance would be adultery, if it could; every covetous desire would be oppression; every thought of unbelief would be atheism, might it grow to its head... It is modest in its first proposals; as it were, in its first motions and proposals; but having once got footing in the heart by them, it constantly makes good its ground, and presseth on to some further degrees in the same kind...

Now nothing can prevent this, but mortification. That withers the root and strikes at the head of sin every hour, so that it is crossed in whatever it aims at. There is not the best saint in the world but, if he should give over this duty, would fall into as many cursed sins as ever any did of his kind."

~John Owen, Mortification of sin (pp.30-31)