What does the Bible say about mourning for sin?

The Bible highlights the importance of mourning for sin, particularly in Matthew 5:4, where it states, 'Blessed are those who mourn, for they will be comforted.' This mourning is not a superficial sadness about earthly loss but a profound sorrow over one’s transgressions against God. It reflects a heart awakened by sovereign grace, which recognizes the seriousness of sin in light of God's holiness. Such heartfelt mourning is a gift from God, as the natural man does not lament his sin deeply; it requires the Holy Spirit to instill such conviction.