"The Lord is our lawgiver" Isaiah 33:22
It is generally accepted among those who profess to adhere to the Judeo-Christian Scriptures that God is the original and great Lawgiver. As with most other things, that is where the agreement ends. There are two principal areas of contention among the different groups: 1) How to define the Law of God and 2) The determination of which parts of it are currently binding on God's people.
For most Jews, there is a sense that "The Law" encompasses the first five books of the Old Testament (what many of them refer to as The Torah). Even among most Christians, I suppose that there is some consensus that all of this material constitutes the "Law of God" or "Law of Moses." However, there are many people who regard the Ten Commandments delivered from Mount Sinai as "God's Law." Likewise, some people would include every commandment, statute, ordinance or judgment recorded anywhere in the Old or New Testaments as "God's Law."
If we are fair, we should all be willing to acknowledge that there is some basis in Scripture for adopting all of these views of "The Law." It should also be apparent to any serious student of the Bible that "The Law" can mean different things in different contexts. Likewise, it would be foolhardy to characterize every law given in Scripture as having equal value or importance - some principles are clearly more important than others.
For Christians, the foremost authority on "The Law" would be Jesus Christ. We read in the Gospel According to Matthew: "Then one of them, which was a lawyer, asked him a question, tempting him, and saying, Master, which is the great commandment in the law? Jesus said unto him, Thou shalt love the Lord thy God with all thy heart, and with all thy soul, and with all thy mind. This is the first and great commandment. And the second is like unto it, Thou shalt love thy neighbor as thyself. On these two commandments hang all the law and the prophets." Matthew 22:35-40
In this passage, we see that Christ characterized two fundamental principles as being the most important ones in the entire law. Indeed, he said that those two principles constituted the basis (the underpinning, if you will) for everything else!
Where did these two principles come from? In answering that question, we would be technically correct to say that Christ was quoting Deuteronomy 6:5 and Leviticus 19:18. Nevertheless, it is also clear that Christ was summarizing the Ten Commandments in this Scripture. The first four commandments defining how to love God, and the last six defining how to love your neighbor.
In his letter to the saints at Rome, the Apostle Paul went on to condense these principles into one concept. He wrote: "Love worketh no ill to his neighbor: therefore love is the fulfilling of the law." Romans 13:10 Christ and Paul didn't see "The Law" as a series of do's and don'ts. They saw that God had a purpose behind those statutes and commandments. Hence, to them, the principle behind the do's and don'ts was what was important and enduring.
Christ once said: "Think not that I am come to destroy the law, or the prophets: I am not come to destroy, but to fulfil. For 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." Matthew 5:17-18 Christ didn't come to the earth to destroy God's Law - He came here to fulfill all of it by obeying every commandment, statute, judgment and ordinance given as part of the "Law of Moses" or "Law of God." To remove the death penalty from us, Christ had to keep it all perfectly. Hence, Christ fulfilled (filled to the full) the requirements of "The Law" on our behalf.
Paul told the Romans that "the carnal mind is enmity against God: for it is not subject to the law of God, neither indeed can be." Romans 8:7 By ourselves, we were incapable of fulfilling the requirements of "The Law." Christ did this for us and thus removed the very things that had separated us from God - our sins (Sin is the transgression of the law - I John 3:4). Thus, we cannot earn our salvation by keeping "The Law" - Christ did that for us. The requirements of the Law have been fulfilled for us - we are under grace. Romans 6:14
Paul continued: "What then? Shall we sin, because we are not under the law, but under grace? God forbid!" Romans 6:15 Christ's fulfillment of the requirements of "The Law" for us was not intended to give us a license to go on sinning. The principles that were and are the basis for God's Law still apply to us today. Christ has made us clean and new - We must not go back to the dirt and the old.