Our purpose is to live with the new covenant.
In Acts 15 it explains how Peter and Paul turned our world upside down. It took the God who only the Hebrews knew and showed the gentiles the true God accepted them, also.
Christ made it possible. Gentiles looked at the rites of the Jews and said "those Jews are strange". Circumcision, diet, not even speaking to a gentile--it kept gentiles away from accepting God. Those things were given by God to help people live by the spiritual laws. Now, the Holy Spirit would help them.
In Jeremiah we are told this covenant is with Israel. (31:30) "Here, the days are coming," says Adonai, "when I will make a new covenant with the house of Isra'el and with the house of Y'hudah.
In Romans we are told we are a branch of Israel.
In Ezekiel we are told what the new covenant is: Eze 37:24 And David my servant shall be king over them; and they all shall have one shepherd: they shall also walk in my judgments, and observe my statutes, and do them.
Eze 37:25
And they shall dwell in the land that I have given unto Jacob my servant, wherein your fathers have dwelt; and they shall dwell therein, even they, and their children, and their children's children for ever: and my servant David shall be their prince for ever.
Eze 37:26
Foreover I will make a covenant of peace with them; it shall be an everlasting covenant with them: and I will place them, and multiply them, and will set my sanctuary in the midst of them for evermore.
Eze 37:27
My tabernacle also shall be with them: yea, I will be their God, and they shall be my people.