How does God comfort those who mourn over sin?

Jesus states in Matthew 5:4 that those who mourn will be comforted. This mourning is a deep recognition of one's sinfulness and need for mercy, which is vital for salvation. The comfort comes through the assurance that God, in His grace, forgives and cleanses those who sincerely repent and seek Him. The acknowledgment of our sin leads us to rely on Christ’s shed blood as the sole source of cleansing. It is in this humility that God's comforting response is distinctly felt, giving us peace and assurance.