Abraham receives the code of circumcision from the Lord God. According to Christianity, Abraham is justified by God because of his faith, just like justified Christians. Without any written scriptures, Abraham's conception of God has many restrictions. Similar to Abraham, many present Christians think they are justified or may be justified with a limited understanding of God. Since the righteousness of God does not change, not only can we know the gradual revelation of God, but also we can study the consistence of faith and righteousness in the Old and New Testament through Abraham's experience and conception of God.