John Frame believes that the Ten Commandments are, essentially, a republication of the creation ordinances (Systematic Theology, p. 75).
Going to have to think about that for awhile.
Has anyone else thought this or is this an original idea with Frame?
I have thought as much for many years. But for Adam, as for us, the Ten Words are only an outline--a summary of the Law of God written in the hearts of our first parents.
Consider Exodus 18:20 (from Jethro's advice to Moses)
And thou shalt teach them ordinances and laws, and shalt shew them the way wherein they must walk,
and the work that they must do.
It seems a developed body of ordinances and laws already were in place before the giving of the Law. Cain and Able must have known the proper manner in which to worship God, what we call the regulative principle.
Genesis 4:3-5
3 And in process of time it came to pass, that Cain brought of the fruit of the ground an offering unto the Lord.
4 And Abel, he also brought of the firstlings of his flock and of the fat thereof.
And the Lord had respect unto Abel and to his offering,
5 But unto Cain and to his offering he had not respect.
And Cain was very wroth, and his countenance fell.
How did they know that they should offer a sacrifice? How did they know what offering(s) to bring? I have heard it said that it was a matter of their hearts that God took notice of, which, of course, must be true. But it must also have been sinfull
will-worship on the part of Cain who decided that since he was a farmer, God would accept his offering. He was wrong in that he did not approach God in a prescribed way. Again demonstrating that there was a body of Law already in place since before the fall.
In Genesis 1:26 "God said, 'Let us make man in our image, after our likeness. And let them have dominion over the fish of the sea and over the birds of the heavens and over the livestock and over all the earth and over every creeping thing that creeps on the earth,?'" Does not the image of God consist in our being "[re]created after the likeness of God in true righteousness and holiness? (Ephesians 4:24) In the garden, there was additionally the positive Law of not eating of the tree on knowledge of good and evil, (Genesis 2:17) But I think that all the Law was part of man's natural makeup, probably excluding the 'temporary' portion of the ceremonial Laws and Moses judicials.
I could add more, but I will wait to see if my preliminary remarks meet with any opposition. I will only add that it is simplistic to think that Adam and Eve had only to name the animals, tend the garden, and have babies.