(As it is written,
I have made you a father of many nations,
) before him whom he believed, even God, who gives life to the dead, and calls those things which are not as though they were.
Read Chapter 4
Paul confirms by quoting the law that Abraham is the father of all who believe, and so the promise is firm if they abandon the law on account of their faith, because the promise of the kingdom of heaven is given to the righteous, not to sinners. Those who are under the law are under sin because all have sinned, and it is not possible for anyone who is under the law to receive grace. In order to teach that there is one God for all, Paul tells the Gentiles that Abraham believed in God himself and was justified in his sight. The Gentiles also believe in him that they may be justified, and so there is no difference between Jew and Greek in faith, for when the circumcision and the uncircumcision are taken away they are made one in Christ. Paul invites the Gentiles to share the faith of Abraham, who believed God while he was still uncircumcised. Now that that faith is preached in Christ, he has been raised from the dead, along with his wife. For when they were already very old they sprang ba...
Is God here referring to the fact that Abraham was the father of the Ishmaelites, or the Amalekites, or the Hagarenes? No … God is a father not by way of natural relationship but by way of the relation of faith. It is in this sense also that Abraham is the father of us all.