Abraham believed God

Therefore He who supplies the Spirit to you and works miracles among you, does He do it by the works of the law, or by the hearing of faith?— just as Abraham “believed God, and it was accounted to him for righteousness.” Therefore know that only those who are of faith are sons of Abraham. And the Scripture, foreseeing that God would justify the Gentiles by faith, preached the gospel to Abraham beforehand, saying, “In you all the nations shall be blessed.” So then those who are of faith are blessed with believing Abraham. – Galatians 3.5-9

So what is our relationship to Abraham? To the Jews of course he was the founder and father of their faith. He was the first Jew and because of that the Jews are sometimes called the children of Abraham.

Abraham was justified by faith – and the scriptures say that through him all the nations of the world would be blessed. So all those who have lived, are living, or will live by faith are blessed through what Abraham did.

No man could become righteous on his own. Abraham believed God and he was accounted righteous. Now, all who have believed God are accounted just as righteous as he was. His pattern of faith was the pattern that would be known to the whole world. All the blessings of eternity that we have today started with ‘Abraham believed God.’