There are two types of moral law; perhaps three. There is natural law, with which we are all born. We soon feel hunger, pain and discomfort. This long ago developed into recognition of the crimes of theft and violence that form the basis of all civil and criminal law, everywhere. It was the law that Abram recognised when he moved from Ur. It was the law that he had in mind when he refused to make improper gain of wealth. It was the law that forced his nephew Lot's escape from Sodom, and the law that destroyed that city. It was the law that Joseph's brothers were conscious of when they were stirred to anger by the rape of their sister Dinah. It was the law that Joseph's brothers were conscious of when they prepared to leave him in a pit. So there was no original absence of law. These moral events and millions more took place before Moses was even born.
It was the law that, by his
faith, Abram obeyed, and it is the law that the sons of Abraham obey now. The law that faithful Sarah obeyed is the law that the daughters of Sarah obey now.
What did Jesus say about that law?
'"Moses permitted you to divorce your wives because your hearts were hard. But it was not this way from the beginning."' Mt 19:8 NIV
Now leniency was not just for marriages, it was for everything in the law of Moses; which is the second kind of law. The Mosaic commandment said, 'Do not murder.' But Jesus said, "Do not even hate." The Mosaic commandment said, 'Do not commit adultery.' But Jesus said, "Do not even lust." And his firmly Mosaic disciples wondered if this was all too much.
So natural law, if observed by the tender conscience, is more searching, and more effective than Mosaic law, because it scrutinises motives. "Is my motive to love, or not?" That is the question that
every human mind should ask, many times, every day; but Satan will certainly try to persuade that the Law of Moses, or even no law at all, is easier, and acceptable.
For those who, through faith, possess the mind of Christ, natural law is 'extended', prompted by the love of Christ, and by gratitude for the forgiveness that is obtained by his sacrifice. So, because of atonement, Paul could write:
'Get rid of all bitterness, rage and anger, brawling and slander, along with every form of malice. Be kind and compassionate to one another, forgiving each other, just as in Christ God forgave you.' Eph 4:31-32 NIV