Hosea tells us that Adam disobeyed the same covenant as Israel (or vice versa).
6 For I desire steadfast love and not sacrifice, the knowledge of God rather than burnt offerings. 7 But like Adam they transgressed the covenant; there they dealt faithlessly with me. (Hosea 6:6-7 ESV)
The word “covenant” has a broader meaning than a specific agreement such as the one at Sinai. There is a built in covenant between God and any created being that assumes a continued reliance on the Creator. He gives life and we continue in that life by abiding in His Word. Normality is to be in God’s Word. Perversity is to be outside of it. A person is created by the Word of God and it is implied that we will stay in that Word because it is life. When we get right down to it there is no sense in departing from the Author of Life. Israel and Adam dealt faithlessly with that Word. Neither was showing steadfast love because neither obeyed the living oracles. That is why Hosea says that they are the same covenant. A covenant of life.
In my opinion the “knowledge of God” mentioned by Hosea is a direct poke at the choice of Adam, because he chose the tree of knowledge over the tree of life (God’s Word). It seems obvious that God’s Word, whether we want to call it a covenant, or promise, or Ten Suggestions, has always been around. Whatever Word He gives us, from “don’t eat that fruit” to “love others as yourself” and everything in between, is part of “the covenant,” because it is all His Word. And all of His Word is binding on His creation all the time, no matter what. To ignore His Word is to be faithless.
When the Law was delivered at Mount Sinai, contrary to standard church teaching, existing Law got written down. It was a condition of His residing with Israel. There were some additions and clarifications, probably due to changing physical circumstance. But by and large, it was the same Law that has always been around. In the midst of the flood of evil threatening to engulf the world, God placed His Ark of the Covenant with the “living oracles” in Israel. Then He set up shop in Israel Himself, as a beacon of life for all men.
From the book Whole Bible Christianity, a draft of which can be viewed at www.wholebible.com/Whole_Bible_Christianity.htm.