Romans 4:2-9

2For if Abraham were justified by works, he hath something to glory about ; but not before God. 3For what saith the scripture? Abraham believed God, and it was counted to him for righteousness. 4Now to him that worketh is the reward not reckoned of grace, but of debt. 5But to him that worketh not, but believeth on him that justifieth the ungodly, his faith is counted for righteousness. 6Even as David also describeth the blessedness of the man, to whom God imputeth righteousness apart from works, 7Saying, Blessed are they whose iniquities are forgiven, and whose sins are covered. 8Blessed is the man to whom the Lord will not impute sin.

9Comeththis blessedness then upon the circumcision only, or upon the uncircumcision also? for we say that faith was reckoned to Abraham for righteousness.