The first reading concludes with God promising, “You will be my people, and I will be your God.”
God was there promising to enter into a covenant with us.
While officiating at a marriage I like asking each party, “Have you come here freely, without reservation, to give yourself to each other in marriage?” By assenting to that the man and the woman give themselves to each other ever in a covenant.
We all know what a contract is. It is the seal on an agreement between parties exchanging things of value. In buying a car or a house you sign a contract to give your money in exchange for the car or the house. Now, a covenant is also a contract, but one of a special kind. For, instead of the parties exchanging things of value to each, they exchange their selves.
Chapter Twenty-four of Exodus describes the ratification of the covenant between God snd his people. While Moses was calling out the terms of the covenant, and the people were assenting, young men carrying brass bowls of blood circulated through the crowd, sprinkling blood on ever person, then poring the rest of the blood on the altar of God. With the people believing blood to be life itself, the people and God were all becoming one life.
While that ceremony in Exodus Twenty-four ratified the Old Covenant. The New Covenant between Jesus and us is ratified in the Mass when the priest speaks these words for Jesus:
“This is the chalice of my blood, the blood of the new and eternal covenant which will be poured out for you and for many.”