The covenant is more than just an agreement between God and the Israelites. It has its own quirks, subtleties, and super-weird moments. And in many ways, Exodus is the covenant book—It's the rules, the history, and the contract all wrapped up into one.
You probably remember Abraham's covenant with God from Genesis. Well, this is an extension of that—version 2.0. Have you ever heard people use the phrase "living constitution?" That's the idea here. The deeper you get into the Hebrew Bible, the more the terms of the covenant are changed depending on who's doing the dealing. In Exodus, freedom is part of the deal, and it's signed in blood.