Eternal Covenants 1: God's Immutable Oath

There are three ways God deals with men: by mercy, by merit and by covenant; and covenant is the highest form of relationship any man can have with God. It is what keeps God committed to you even when you fail, it gives you access to everything God owns and vice versa. It is the Oath of God signed in Blood. In fact, the scriptures tells us that there are two immutable things that makes it impossible for God to lie: His Word and His Covenant. So, what are Eternal Covenants and how can we enter them?