Proverbs 25:19
"Confidence in an unfaithful man in time of trouble is like a broken tooth, and a foot out of joint."
Cross References (ranked by relevance)
Isaiah 36:6
Lo, thou trustest in the staff of this broken reed, on Egypt; whereon if a man lean, it will go into his hand, and pierce it: so is Pharaoh king of Egypt to all that trust in him.
2 Timothy 4:16
At my first answer no man stood with me, but all men forsook me: I pray God that it may not be laid to their charge.