The covenant between God and Abraham was outwardly marked by circumcision, but circumcision did not make Abraham righteous, rather, his faith in God was credited to him as righteousness, before he was circumcised. It is better to be an uncircumcised gentile who does what the law commands, than a circumcised Jew who knows God’s law but disobeys it. Knowledge, works, and family heritage won’t produce righteousness in us apart from Christ, only the Spirit’s work to conform us to the image of Christ can produce righteousness in us because we have a changed heart.