Hebrews 8 is unique for at least two reasons: First, it contains the longest quote from the Old Testament in the New Testament. Second, because it contains that long quote, you’d expect the writer to do a lot with it; kinda like the preacher using a long text to preach a series of sermons.
But the writer of Hebrews doesn’t. He focuses on only one word: “new.” God has made a “new” covenant.
There are several covenants in the Old Testament, but the most important one is that made with Israel at Sinai. Virtually the entirety of the Old Testament deals with that one, and from it we can learn several important facts:
First, covenants are “agreements.”
Second, God initiates covenants with mankind. Not the other way around.
Third, all blessings from God are tied inseparably to a covenant, and without a covenant, there is no blessing.
Fourth, covenants are so important that they are sealed with blood.
Fifth, while covenants entail responsibilities, responsibilities do not always entail covenants. God holds mankind – all mankind – responsible for how he lives: he is required to live God’s way. But that doesn’t mean if he does, he is in covenant with God nor does it mean he can expect blessing.
The covenant of the Old Testament promised blessing only to Israel. But the “new” covenant opens the door of blessing to all people. It was initiated by God, and made possible through his blood, the blood of Jesus. All who enter this covenant through the death of Christ (symbolized by baptism) have entered this special relationship. The implication is that because we have entered it, our lives should be different too – especially different from those outside the covenant.