Jeremiah 17:9,10

Had we no other authority than what these verses furnish, here is enough to prove, that after all our knowledge of ourselves, we have not arrived to the perfect apprehension to what a state of sin and self-deception man is reduced by the fall. But however ignorant we are of ourselves to the Lord, the most secret thoughts of our heart are open. What an argument ariseth from hence, to beg the Lord to cleanse us from our secret faults, and to bring us to the fountain opened for sin and for uncleanness. Psalms 19:12; Zechariah 13:1.