You are aware of the Covenant of Moses. Regular readers are surely aware of the Covenant of Noah.
What you may not understand is that Moses was a particular application of Noah. Moses was restricted to a specific people, time and place. The Talmud means nothing in our consideration; it’s a perversion of Moses. But Moses was the one covenant best explained, so it serves as an example, and our duty is to study it so we can discern what it tells us about God and His ways (2 Timothy 2:15).
Moses was a suzerain-vassal treaty, an instance of ANE feudalism. As such, it is an approximation of how God wants us to relate to Him, and indicates how Creation (or reality) works. You have to understand it organically. It does yield to study, but no two of us could possibly see the exact same thing — that’s what “organic” means in this context. You don’t grasp it intellectually; you absorb it as the true nature of your own existence.
The Covenant of Christ is the final endpoint of all covenants in the Bible. Jesus is the ultimate revelation of God and His ways. In that sense, He personally is as close as we can come to knowing the Creator. He is thus the living embodiment of all covenants; He is the Final Covenant. He is the Law of God, the summation of Scripture.
Thus, “Biblical Law” is an organic grasp of God’s moral character. I can cite various ideas as part of Biblical Law, but there is no way to cite the Law itself. Nonetheless, it implies a body of law in the sense that I can point to something as moral or immoral and your heart is quite likely to recognize what I’m suggesting. It’s not meant to compel your assent; it’s meant to awaken your discernment.
What you or I might have to say about what is moral or immoral — according to Biblical Law — will depend on how well we have delved into ANE history and culture. We might instinctively understand any number of things we cannot put into words, but we do know that God built the ANE heritage as the context for revelation. If we can talk in terms of ANE heritage, then we can talk about revelation. Notice how some of these terms I use overlap and point to pretty much the same inexpressible thing: Biblical Law, the Person of Jesus Christ, the gospel message, divine revelation, Scripture, etc. You choose a different term for a different context, but we are reaching for the same basic matter of faith.