Jesus answered and said to them, “Because of your hardness of heart he wrote you that commandment.
Christ reveals the root of the issue: hardness of heart. Moses’ regulation was given not because divorce was pleasing to God, but because the people’s hearts had become hardened, and their sinful condition required certain arrangements in order to prevent a greater evil. Hardness of heart is the state in which a person does not want to love, forgive, be patient, and remain faithful to the covenant. The Lord shows that the breaking of marriage often begins not from outward circumstances, but from inner rigidity. This word also reminds us that God’s law sometimes tolerates certain things in order to restrain a greater evil arising from human fallenness, but that never means that they express His perfect will.