The true believers, regardless of Jew or Gentile, are the Israel of God who will be gathered at Christ's return.
Deu 30:1 And it shall come to pass, when all these things are come upon thee, the blessing and the curse, which I have set before thee, and thou shalt call them to mind among all the nations, whither the LORD thy God hath driven thee,
Deu 30:2 And shalt return unto the LORD thy God, and shalt obey his voice according to all that I command thee this day, thou and thy children, with all thine heart, and with all thy soul;
Deu 30:3 That then the LORD thy God will turn thy captivity, and have compassion upon thee, and will return and gather thee from all the nations, whither the LORD thy God hath scattered thee.
Deu 30:4 If any of thine be driven out unto the outmost parts of heaven, from thence will the LORD thy God gather thee, and from thence will he fetch thee:
Deu 30:5 And the LORD thy God will bring thee into the land which thy fathers possessed, and thou shalt possess it; and he will do thee good, and multiply thee above thy fathers.
Deu 30:6 And the LORD thy God will circumcise thine heart, and the heart of thy seed, to love the LORD thy God with all thine heart, and with all thy soul, that thou mayest live.
Deu 30:7 And the LORD thy God will put all these curses upon thine enemies, and on them that hate thee, which persecuted thee.
Deu 30:8 And thou shalt return and obey the voice of the LORD, and do all his commandments which I command thee this day.
Deu 30:9 And the LORD thy God will make thee plenteous in every work of thine hand, in the fruit of thy body, and in the fruit of thy cattle, and in the fruit of thy land, for good: for the LORD will again rejoice over thee for good, as he rejoiced over thy fathers:
Deu 30:10 If thou shalt hearken unto the voice of the LORD thy God, to keep his commandments and his statutes which are written in this book of the law, and if thou turn unto the LORD thy God with all thine heart, and with all thy soul.
Deu 30:11 For this commandment which I command thee this day, it is not hidden from thee, neither is it far off.
Deu 30:12 It is not in heaven, that thou shouldest say, Who shall go up for us to heaven, and bring it unto us, that we may hear it, and do it?
Deu 30:13 Neither is it beyond the sea, that thou shouldest say, Who shall go over the sea for us, and bring it unto us, that we may hear it, and do it?
Deu 30:14 But the word is very nigh unto thee, in thy mouth, and in thy heart, that thou mayest do it.
ALL Pauls doctrine came from the OT. by revelation from God.
Rom 10:6 But the righteousness which is of faith speaketh on this wise, Say not in thine heart, Who shall ascend into heaven? (that is, to bring Christ down from above
Rom 10:7 Or, Who shall descend into the deep? (that is, to bring up Christ again from the dead.)
Rom 10:8 But what saith it? The word is nigh thee, even in thy mouth, and in thy heart: that is, the word of faith, which we preach;
Rom 10:9 That if thou shalt confess with thy mouth the Lord Jesus, and shalt believe in thine heart that God hath raised him from the dead, thou shalt be saved.
Rom 10:10 For with the heart man believeth unto righteousness; and with the mouth confession is made unto salvation.
Rom 10:11 For the scripture saith, Whosoever believeth on him shall not be ashamed.
LA