Many of the House of Israel became Christians.
Christianity itself is a sect of 2nd temple Judaism.
What we call Judaism today is a sister sect of Christianity. The proper term is rabbinical Judaism which has the Talmud and Halacha in lieu of the New testament.
There is no more Jew nor Greek.
Sure there is...In Israel there are millions of Jews...And in Rome there are countless Greeks...
It is only in Jesus Christ where there are no Jews or Greeks...We are all one...