The fact that Paul mentions Abraham throws off many a person.
Fact of the matter is that are two people and Abraham is the father of both....those who "followed that righteousness which is of the Law" who also walked in that faith that Abraham had...and those under "that righteousness which is of faith" alone...for their same faith of Abraham...
Romans 4:11 And he received the sign of circumcision, a seal of the righteousness of the faith which he had yet being uncircumcised: that he might be the father of all them that believe, though they be not circumcised; that righteousness might be imputed unto them also: 4:12 And the father of circumcision to them who are not of the circumcision only, but who also walk in the steps of that faith of our father Abraham, which he had being yet uncircumcised.
Romans 4:16 Therefore it is of faith, that it might be by grace; to the end the promise might be sure to all the seed; not to that only which is of the law, but to that also which is of the faith of Abraham; who is the father of us all,
There are not two peoples of faith in Christ--
Only one people--
Eph 2:11 Wherefore remember, that ye being in time past Gentiles in the flesh, who are called Uncircumcision by that which is called the Circumcision in the flesh made by hands;
Eph 2:12 That at that time ye were without Christ, being aliens from the commonwealth of Israel, and strangers from the covenants of promise, having no hope, and without God in the world:
Eph 2:13 But now in Christ Jesus ye who sometimes were far off are made nigh by the blood of Christ.
Eph 2:14 For he is our peace, who hath made both one, and hath broken down the middle wall of partition between us;
Eph 2:15 Having abolished in his flesh the enmity, even the law of commandments contained in ordinances; for to make in himself of twain one new man, so making peace;
Eph 2:16 And that he might reconcile both unto God in one body by the cross, having slain the enmity thereby:
Eph 2:17 And came and preached peace to you which were afar off, and to them that were nigh.
Eph 2:18 For through him we both have access by one Spirit unto the Father.
Eph 2:19 Now therefore ye are no more strangers and foreigners, but fellowcitizens with the saints, and of the household of God;
Eph 2:20 And are built upon the foundation of the apostles and prophets, Jesus Christ himself being the chief corner stone;
Eph 2:21 In whom all the building fitly framed together groweth unto an holy temple in the Lord:
Eph 2:22 In whom ye also are builded together for an habitation of God through the Spirit.
and they are all children of God through faith in Christ--
Gal 3:21 Is the law then against the promises of God? God forbid: for if there had been a law given which could have given life, verily righteousness should have been by the law.
Gal 3:22 But the scripture hath concluded all under sin, that the promise by faith of Jesus Christ might be given to them that believe.
Gal 3:23 But before faith came, we were kept under the law, shut up unto the faith which should afterwards be revealed.
Gal 3:24 Wherefore the law was our schoolmaster to bring us unto Christ, that we might be justified by faith.
Gal 3:25 But after that faith is come, we are no longer under a schoolmaster.
Gal 3:26 For ye are all the children of God by faith in Christ Jesus.
Gal 3:27 For as many of you as have been baptized into Christ have put on Christ.
Gal 3:28 There is neither Jew nor Greek, there is neither bond nor free, there is neither male nor female: for ye are all one in Christ Jesus.
Gal 3:29 And if ye be Christ's, then are ye Abraham's seed, and heirs according to the promise.
LA
