Examine your own hearts. Do you see there any habit or custom which you know is wrong in the sight of God? If you do, don't delay for a moment in attacking it. Resolve at once to lay it aside. Nothing darkens the eyes of the mind so much, and deadens the conscience so surely, as an allowed sin. It may be a little one, but it is not any less dangerous.
"Thoughts for Young Men". Book by J. C. Ryle, June, 2002.