Man in the jungle or hunting stage had to be greedy – to seek food eagerly and gorge himself zealously – because, when food came, he could not be sure when it would come again. He had to be sexually sensitive, often promiscuous, because a high death rate compelled a high birth rate; every woman had to be made a mother whenever possible, and the function of the male was to be always in heat. He had to be pugnacious, ever ready to fight for food or mate. Vices were once virtues, indispensable for survival.
But when man found that the best means of survival, for individual as well as for species, was social organization, he expanded the hunting pack into a system of social order in which the instincts once so useful in the hunting stage had to be checked at every turn to make society possible. Ethically every civilization is a balance and tension between the jungle instincts of men and the inhibitions of a moral code. The instincts without the inhibitions would end civilization; the inhibitions without the instincts would end life. The problem of morality is to adjust inhibitions to protect civilization without enfeebling life.William Durant, The Age of Faith (New York: Simon and Schuster, 1950), p. 819.
... Render unto Caesar the things which are Caesar’s; and unto God the things that are God’s.KJV Matt. 22:21
There are rules in this world that are enforced because they maintain civilization (as described in the quote by William Durant above). There are rules enforced because they save the souls of men. The rules that save the souls of men enjoy supernatural law enforcement. God is all seeing and all knowing, therefore these laws cannot be broken without either being atoned for or ultimately punished. Some rules aimed to maintain civilization are presented as rules that save the souls of men because they are difficult to enforce (e.g., sexual morality). But really, these rules belong to Caesar rather than God.
The rules belonging to Caesar are important, just not ultimately important. They should be enforced if maintaining civilization is a priority. But as Jesus articulates in Matthew 22:21, the things that belong to Caesar should not be confused for the things that belong to God.