Psalms 51:2

Psalms 51:2. Wash me throughly from mine iniquity.

"Wash me through and through, O Lord; wash me thoroughly!" A hypocrite is satisfied with the washing of his garments, but the true penitent cries, "Wash me. Wash me throughly from mine iniquity. It is almost the only thing that I can really call my own, and it is most sadly mine, O Lord, wash mine iniquity right away!"

Psalms 51:2. And cleanse me from my sin.

"If washing will not suffice, put me in the fire; but somehow, anyhow, O Lord, cleanse me from my sin!" You notice that David’s prayer is not concerning the punishment of his sin, but concerning the sin itself. That is the one thing which is eating into his heart; see how many words he uses to describe it: "My sin, mine iniquity, my transgressions." He cries to God to help him to get rid of that which is the source of all his sorrow. The thief dreads the gallows, but the penitent fears not the punishment of his sin, it is the sin itself that terrifies him.