What does the Bible say about repentance and sin?

Repentance, as articulated in Psalm 51, signifies a profound acknowledgment of one's sinfulness and a sincere turning towards God for grace and forgiveness. David, the psalmist, emphasizes the importance of recognizing the gravity of both his sinful nature and specific transgressions. He prays for mercy not based on his own righteousness or sorrow, but solely on God's loving kindness and multitude of tender mercies. This reflects a heart that understands true repentance, which is a change of mind about sin and a deep need for divine grace.