The word ‘mercy’ in Hebrew is used about 250 times in the Old Testament, and refers to God’s gracious love. It is a comprehensive term that encompasses love, grace, mercy, goodness, forgiveness, truth, compassion, and faithfulness. The bedrock of faith is the reality that God keeps all His promises according to His truthful, faithful character.
Commentary from the MacArthur study Bible, notes for Lamentations 3:22, 23.