There used to be a general acknowledgement of something called natural law.  The gist I suppose, would be to say that there are certain things that human beings cannot help but know are wrong.  They are “written on the heart” and human beings violate them by ignoring their conscience.  Because of the flexibility of conscience and the human ability to self justification, Prophet voices hammered that Law home in the Old Testament.  Theodore Laetch wrote back in 1940 about the Law of God and the social order (CTM Vol XI).

“Wherever the social order as demanded by the Lord was maintained and complied with, this was due to the untiring efforts of the prophets of God and their conscientious preaching of God’s Word without addition or diminution. And wherever prophets so called, deviated from the Word of God or the people refused to hear and obey the faithful spokesmen of God, deterioration, disintegration of the social order, set in and increased in the same ratio that the setting aside of God’s Word became the accepted fashion of the times. Once more let us recall to memory that all the social messages of the prophets of which we have taken notice so far are addressed to Israel, the theocratic nation, divinely instituted as such. The prophets had messages also for the surrounding Gentile nations, and many of their proclamations to these nations or to individual members touched upon social questions. Consistent with their call to be spokesmen of God, they preached these messages with the same scrupulous avoidance of any addition or diminution. They left the Law of God unchanged, that Moral Law which obligates every human being to unselfish service of God and his fellow-man, that Law which God has inscribed into man’s heart. this Moral Law they proclaimed just as God had given it, without omitting or altering one jot or tittle of its demands, of its threats, of its universal obligation.”

Because the Law is God’s Law it has a universal obligation. It is not our morality that we are trying to impose on others, it is a universal obligation place upon all human beings because they are human beings.  The call of the Law is to unselfish service to God and our fellow man.