Paul expands the defense of his gospel against slanderous charges from competing Jewish “authorities” to now include the biblical and Jewish heroes: Abraham and King David. Paul demonstrates that the Bible teaches both Abraham and David were justified before God by faith, and that is the only way any human can be justified before God.
The competing Jewish “authorities” are arguing that we must do our part in order to be justified before God. Paul is now going to use Abraham as more proof that justification comes through faith and not through anything we can do.
No one can do enough good works so that God owes them. Everyone is sinful and cannot cause themselves to be in righteous standing before God. However, if we believe God, our faith is credited to us as righteousness, making us just before God.
It is God’s blessing to us that God considers believers righteous before him without considering their sins. By faith in God, our sin is covered and cannot prevent us from being in God’s family.
The blessing of having our sins forgiven is available to all, circumcised or uncircumcised.
Paul is emphasizing that Abraham is the father of all who believe, whether circumcised or uncircumcised.
The law is abolished through Christ, so if the promise was made through the law, then God would have broken His promise to Abraham. The promise God made to Abraham was apart from the law: it was through faith.
No one can live up to God’s standard; we are saved by grace through faith.
By all human standards, it was impossible for Abraham and Sarah to have a child, but Abraham believed God’s promise anyway. Even though Abraham did not understand how, he was convinced that God would accomplish what He promised.
When Abraham believed God, he was counted as righteous in God’s sight. It is the same with us, when we believe God we are counted as righteous.
Abraham was credited as righteous because of his faith. If we have faith that Christ died for our sins and was raised from the dead and that alone can make us right in the sight of God we also will be counted as righteous.