Before Sinai, God’s law has existed at least as long as sin has existed. The Bible says, “Where no law is, there is no transgression [or sin]” (Romans 4:15). According to the Bible, the definition of sin is “For sin is the transgression of the law” (1 John 3:4). Man could not exist with out the moral Law. If the moral law were rescinded, there would be no safe place on earth for anyone. The first four commandments define our responsibility to our Creator. The last six are the foundation of all human civil law. The Ten Commandment law is God’s character in written form–written so we can comprehend it “All his commandments are sure. They stand fast for ever and ever” (Psalms111:7, 8).
Originally, the laws came from Adam orally straight out of the Garden of Eden and became part of the oral tradition. In addition, Adam and Eve were created in the image of God, so they knew their Father’s character, which is revealed in the Ten Commandments (Romans 7:12; Psalms 19:7; Psalms 119:172). They passed this knowledge to their offspring. The Bible tells us that God wrote the law in the hearts of the people (Romans 2:15).
Also, Abraham who lived before Sinai knew and kept God’s Law “Because that Abraham obeyed my voice, and kept my charge, my commandments, my statutes, and my laws” (Genesis 26:5). Abraham diligently kept them all, whether they came directly from God or whether they had been handed down from past generations. He set in his heart to obey God fully; where he failed, he approached God with the sacrifice of contrition upon the altar of his heart (Heb. 7:25; 8:1–4)
By the time of Moses and Sinai, after the people had been in slavery in Egypt, and thereby under the influence of the Egyptian pagan religion, their memory had been corrupted somewhat. So, God ultimately wrote the Ten Commandments Lawon two tables of stone so there will not be any confusion about what is right and wrong (Exodus 31:18; 32:16).
In His service,