Romans 4:11-13

4:11 And he received the sign of circumcision as a seal of the righteousness that he had by faith while he was still uncircumcised, so that he would become the father of all those who believe but have never been circumcised, that they too could have righteousness credited to them. 4:12 And he is also the father of the circumcised, who are not only circumcised, but who also walk in the footsteps of the faith that our father Abraham possessed when he was still uncircumcised.

4:13 For the promise to Abraham or to his descendants that he would inherit the world was not fulfilled through the law, but through the righteousness that comes by faith.

Romans 4:17-18

4:17 (as it is written, “I have made you the father of many nations”). He is our father in the presence of God whom he believed – the God who makes the dead alive and summons the things that do not yet exist as though they already do. 4:18 Against hope Abraham believed in hope with the result that he became the father of many nations according to the pronouncement, “so will your descendants be.”