Proverbs 20:9

Who can say, I have made my heart clean, I am pure from my sin?

No one can truthfully claim to have made his own heart clean by himself or to be pure from his sin. Human beings are unable to cleanse the deep source of sin within themselves or to erase the traces of original sin. A clean heart must therefore be sought from God, as David did when he prayed for God to create one within him. Purity is received by faith working through obedience, not achieved by human effort alone. Jesus Christ cleanses the heart from sin when His Word is received by faith.