Not all Israel is born again Israel as those who do have the born again Spirt of Christ. Just as not all who say they are a Jew are. Being a Jew has to do with the unseen inward born again manner of spirit not outwardly according to what the eyes see.
Romans 2:22-29 King James Version (KJV) For he is not a Jew, which is one outwardly; neither is that circumcision, which is outward in the flesh: But he is a Jew, which is one inwardly; and circumcision is that of the heart, in the spirit, and not in the letter; whose praise is not of men, but of God.
The Jews that had the outward identification according to the flesh where reminded it profits for nothing .Just as Jesus said of his own Jewish flesh . . it profits for zero.
Our father who propmised in Isaiah he would rename his bride previously called Israel became "Christian". It came about in Acts. Christian a more befitting name to represent a bride made up of all the nations.
Christian literally meaning residents of the City of Christ prepared as the one bride of made up of all the nation .Named after her husband and founder Christ.
Salvation has nothing to do with DNA.
Revelation 2:9I know thy works, and tribulation, and poverty, (but thou art rich) and I know the blasphemy of them which say they are
Jews, and are not, but are the synagogue of Satan.
Revelation 3:9 Behold, I will make them of the synagogue of Satan, which say they are
Jews, and are not, but do lie; behold, I will make them to come and worship before thy feet, and to know that I have loved thee.
A Christian falls under the same category of a born again Israelite or a inward Jew .