Was God's law available prior to Sinai?

⮜ Answered Questions

God established civil government right after the Flood, as recorded in Genesis: 6 Whoever sheds man’s blood, his blood will be shed by man, for God made man in his own image. Genesis 9:6WEB

After this, God revealed a detailed set of statutes (probably directly to Noah and his family). We can infer this from four things:

1. The plain "blood for blood" statement in Gen. 9:6 is not sufficient, in itself, to guide the type of action which YHWH is commanding. Consider the following questions which Noah might have had, after hearing this simple statement:
   1. Any shedding of blood? Or is "blood" merely a metonym for killing?
   2. Any killing? Or is killing in self-defense lawful? How about killing in defense of others?
   3. What if the "shedding of blood" is accidental (an axe head flies off: Deut. 19:5)? Is there still blood-guilt?
   4. What are the judicial procedures which must be followed when rendering YHWH's retributive justice? How many witnesses are required? What if the witnesses lie?
      
      I could multiply questions, but you get the point. God doesn't just give ambiguous commands to kill in response to killing. He supplies additional guidance, and he must have done so to Noah. In scripture, we have a record of four separate instances in which even Moses had to go back and ask YHWH directly for clarification on the law which he had been given. Are we expected to believe that Noah would know everything which a civil judge needed to know merely by hearing YHWH's sentence in Genesis 9:6?
2. We also have a scripture reference to the comprehensive, pre-Sinai law in God's statement about Abraham:5 because Abraham obeyed my voice, and kept my requirements, my commandments, my statutes, and my laws.” Genesis 26:5WEB The terms "commandments, statutes, and laws" are used together elsewhere in scripture (e.g. Deut.11:1) to denote the whole of God's law. This implies that God's detailed laws were given prior to the ones associated with the Sinai Covenant. Merely because we do not have a record of certain laws and instructions which God gave, doesn't mean that he didn't give them. We infer their existence by "good and necessary consequence."
3. The book of Genesis contains extensive references and allusions to detailed laws covering a similar scope to the ones we find in the other four books of the Pentateuch. It implies a legal framework that encompasses (at a minimum) contract law, family law (including levirate marriage), criminal law, covenants, treaties, and judicial procedure.
4. The Apostle Paul states that "sin is not reckoned when there is no law," (Rom. 5:13). Yet sin was reckoned against many people groups in the pre-Sinai era, including Sodom and Gomorrah and the Amorites. For example, YHWH told Abraham about the sins which he was reckoning against the Amorites four-hundred years before he would judge them for their sin:16 In the fourth generation they will come here again, for the iniquity of the Amorite is not yet full.” Genesis 15:16WEB Therefore, the Amorites (and all the other peoples in the land of Canaan: Lev. 18:26-30, Deut. 18:9-14) must have had a form of God's law (including the very specific regulations itemized in Leviticus 18 and Deuteronomy 18), otherwise their sin would not have been reckoned to them (a reckoning which brought total destruction to their peoples). Wherever we see God's temporal judgment at work, we can be certain that he made his law available to those people groups. Otherwise, we would have to disagree with Paul's statement in Rom. 5:13.

Therefore, a set of detailed laws, judicial and evidential procedures and punishments must have been available prior to Sinai.