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, (As it is written, I have made thee a father of many nations,) before him whom he believed, even God, who quickeneth the dead, and calleth those things which be not as though they were. ~ Romans 4:16-17 KJV

Therefore, the promise comes by faith, so that it may be by grace and may be guaranteed to all Abraham’s offspring—not only to those who are of the law but also to those who are of the faith of Abraham. He is the father of us all. As it is written: ”I have made you a father of many nations.” He is our father in the sight of God, in whom he believed—the God who gives life to the dead and calls things that are not as though they were. ~ Romans 4:16-17 NIV (1984)

Therefore, [inheriting] the promise is the outcome of faith and depends [entirely] on faith, in order that it might be given as an act of grace (unmerited favor), to make it stable and valid and guaranteed to all his descendants–not only to the devotees and adherents of the Law, but also to those who share the faith of Abraham, who is [thus] the father of us all. As it is written, I have made you the father of many nations. [He was appointed our father] in the sight of God in Whom he believed, Who gives life to the dead and speaks of the nonexistent things that [He has foretold and promised] as if they [already] existed. ~ Romans 4:16-17 AMP