What does Psalm 51 teach about sin and its consequences?

In Psalm 51, David explicitly acknowledges the gravity of his sin, stating, 'Against thee, thee only, have I sinned' (Psalm 51:4). This highlights that all sin is ultimately against God, leading to separation from Him. The consequences of sin are serious, as expressed through David's plea for mercy and cleansing. He understands that sin can only be dealt with through the grace of God and the sacrifice of Christ, pointing us to the necessity of repentance to restore fellowship with the Lord.