Let us look at this passage where we see the New Covenant promised to the house of Israel and the house of Judah:
"Behold, the days come, saith the LORD, that I will make a new covenant with the house of Israel, and with the house of Judah: Not according to the covenant that I made with their fathers in the day that I took them by the hand to bring them out of the land of Egypt; which my covenant they brake, although I was an husband unto them, saith the LORD: But this shall be the covenant that I will make with the house of Israel; After those days, saith the LORD, I will put my law in their inward parts, and write it in their hearts; and will be their God, and they shall be my people. And they shall teach no more every man his neighbour, and every man his brother, saying, Know the LORD: for they shall all know me, from the least of them unto the greatest of them, saith the LORD: for I will forgive their iniquity, and I will remember their sin no more" (Jer.31:31-34).
The "fathers" of the ones who will receive the New Covenant were the physical descendants of Abraham, Issac and Jacob, the ones who broke the covenant. And since the fathers are the physical descendants of Abraham, Isaac and Jacob then that means that the offspring of those fathers will also be the physical descendants of Abraham, Isaac and Jacob.
So in the future all of the house of Israel and all of the house of Judah which will be made up of the physical descendants of Abraham, Isaac and Jacob and they will all, from the least of them unto the greatest of them, will have their sins forgiven and be saved.
You are so confused that you think that the house of Israel is referring to Gentiles despite the fact that the fathers of those of the house of Israel are the physical descendants of Abraham, Isaac and Jacob!
Your spiritual I.Q. is practically ZERO!