O.T. – N.T.
Old Testament - New Testament
Many think the Old Testament values are obsolete.
However, Jesus stated, in Mathew 5: 17Think not that I am come to destroy the law, or the prophets: I am not come to destroy, but to fulfil. 18For verily I say unto you, Till heaven and earth pass, one jot or one tittle shall in no wise pass from the law, till all be fulfilled. 19Whosoever therefore shall break one of these least commandments, and shall teach men so, he shall be called the least in the kingdom of heaven: but whosoever shall do and teach them, the same shall be called great in the kingdom of heaven. 20For I say unto you, That except your righteousness shall exceed the righteousness of the scribes and Pharisees, ye shall in no case enter into the kingdom of heaven. 
The biblical definition of the law; from general to specific; incorporates, God's Word, the Old testament, the Pentateuch (5 books of Moses = Genesis to Deuteronomy), summated in THE 10 COMMANDMENTS:
God says, He does not change; His moral values do not change, nor does He compromise them. God's moral values have not changed before or after Creation, the Flood, Old Testament or New Testament times. God does adjust how He deals with us in different circumstances:
In Old Testament times, the nation of Israel was a Theocracy under God. The 'Law of God' comprised:
In New Testament times, God knowing that Christians would be living in diverse circumstances in many nations under different governing civil authorities, His instructions primarily addressed Communal conduct & enforcement:
The obvious civil authoritative structure for any sovereign entity, professing Christian values, to adopt, is the Old Testament, primarily the Pentateuch (5 books of Moses), primarily the civil laws in Exodus through Deuteronomy.
The King James Version, (Cambridge: Cambridge) 1769.