Unfaithfulness and the Ethic of the Kingdom

Love is the essence of the kingdom's ethic, and so Jesus appropriately began His treatment of that ethic by considering the general interpersonal enmity that is fundamental to all human relationships in the old Adamic order. From there He turned His attention to a close counterpart, namely the enmity - that is, the lovelessness - that exists within the marital relationship. Specifically, Jesus used the Decalogue's seventh commandment forbidding adultery to show how adultery ultimately concerns marital lovelessness, regardless of whether spouses remain physically faithful to one another. Adultery is a matter of the heart, and this is the reason that even an apparently justified divorce can render a person an adulterer. In the kingdom of heaven, obedience to God's commandments consists in conformity to the law of love.