Yes, that is true for Salvation. However, Gentiles are grafted into the Jewish Olive Tree. Israel is GOD THE FATHER’S wife. Replacment Thelogy says that GOD has changed his Covenant with Israel, he has not. I5 is a doctrine of demons.
See, days are coming—oracle of the LORD—when I will make a new covenant with the house of Israel and the house of Judah. (Jeremiah 31:31)To hold on to the old covenant which has been expanded and fulfilled in the new is to disobey God, to worship the Jewish ethnicity rather than God. The one covenant in Jesus Christ is for all, Jews and non-Jews alike. There is no other. The present Jewish state is purely a modern secular endeavor. It is has nothing to do with the old covenant.With them I will make an everlasting covenant [will make, i.e., in the future, not the then present covenant], never to cease doing good to them; I will put fear of me in their hearts so that they never turn away from me. (Jer. 32:4)
For this reason he is mediator of a new covenant: since a death has taken place for deliverance from transgressions under the first covenant, those who are called may receive the promised eternal inheritance. (Hebrews 9:14)