Thus Abraham "believed God, and it was reckoned to him as righteousness."
So you see that it is men of faith who are the sons of Abraham.
And the scripture, foreseeing that God would justify the Gentiles by faith, preached the gospel beforehand to Abraham, saying, "In you shall all the nations be blessed."
So then, those who are men of faith are blessed with Abraham who had faith.
Revised Standard Version of the Bible, copyright 1952 [2nd edition, 1971] by the Division of Christian Education of the National Council of the Churches of Christ in the United States of America. Used by permission. All rights reserved. (Revised Standard Version w/ Apocrypha)