Sin results in 1) condemnation, 2) guilt, 3) defilement, and 4) estrangement from God. Justification deals with #1 absolutely, but 3-4 in a non-absolute way in this life. There is still culpability, and a defiling, alienating effect when Christians sin, and the remedy is confession. According to Paul, David had sound teaching on the doctrine of justification by faith in Ps.32 (where he confesses sin), which means Ps.51 is a good place to learn how confession should look. He asks for forgiveness, cleansing, and restoration of the joy of nearness to God. Sin detonates a bomb in your heart that requires nothing short of re-creation. Praise God that He is a re-Creator!