Note that it was not enough to simply make an affirmation of the covenant verbally: the terms of the covenant were sealed by sacrifice. Animals were killed and offered to YHVH and their blood was sprinkled on the altar and on the people. As Moses sprinkled the people he declared solemnly: “The blood of the covenant which the LORD has made with you according to all these words.”
The New Covenant
Some Christians assume that the New Covenant is really intended for the Christian Church which has somehow replaced Israel in God’s plan. This is not true. The New Covenant, or B’rit Chadashah, is mentioned only one time in the Tanakh (Jeremiah 31:31-33) and is explicitly addressed to the Jewish people:
"Behold, the days are coming, declares the LORD, when I will make a new covenant (b’rit chadashah) with the house of Israel and the house of Judah, not like the covenant that I made with their fathers on the day when I took them by the hand to bring them out of the land of Egypt, my covenant that they broke, though I was their husband, declares the LORD. But this is the covenant that I will make with the house of Israel after those days, declares the LORD: I will put my law (Torah) within them, and I will write it (the Torah) on their hearts. And I will be their God, and they shall be my people. (Jeremiah 31:31-33 ESV)
This is a covenant for and with the people of Israel, not instead of them. Non-Jewish Christians are made partakers of the covenant promises given to Israel (Ephesians 2:12) but they do not replace the Jewish people as the recipients of God’s covenantal purposes and election (Romans 11:28). Remember, dear Christian: you are not the root, but the root (Israel) bears you (Romans 11:18).
As the Apostle Paul teaches, God introduced a “mystery” to the New Covenant (Romans 11:25) that offered non-Jews special grace to enter into the New Covenant. Why? In order to make Jewish people jealous and draw them back to the God of Abraham, Isaac, and Jacob (Romans 11:11). Paul knew that God would again open the eyes of Israel and save them in the future (Romans 11:27-29) and that He would never cast them away.
Ultimately, then, the New Covenant is an “already/not yet” state of affairs. Already the Mashiach Yeshua has come and offered Himself up as Kapparah for our sins; already He has sent the Ruach Hakodesh to write the Torah upon our hearts; already He is our God and we are His people.
However, the New Covenant will not be ultimately completed until national Israel is entirely back in their ancient homeland and turned to Yeshua HaMashiach as their Savior and LORD. In the meantime, we are in a period of mysterious grace, wherein we have opportunity to offer the terms of the New Covenant to people of every nation, tribe and tongue. When the “fullness of the Gentiles” is come in, God will turn His full attention to completing His covenant with Israel. Maranatha!