The Abrahamic Covenant promised that Abraham's seed would become a great nation. This was fulfilled by the Sinaitic Covenant. Exodus 19:5-6 shows us that the Sinaitic Covenant established the People of Israel as a nation. Jeremiah 31 shows us that the New Covenant is a reaffirmation of the national covenant (Sinaitic) because it makes explicit references to the nation and to the constituent Houses of the nation. Yeshua tells us that His blood is the blood of the New Covenant. Therefore, partners in the New Covenant are members of the nation of Israel.