Romans 4:3

For what saith the Scripture?
&c.] This answers to (bytkd) (yam) , "what is that which is written" ^F3? or what does the Scripture say? which is a way of speaking used by the Jews, when anything is proposed, which seems contrary to Scripture, as here justification by works does. A testimony from Scripture is here produced, proving that Abraham was justified by faith, and not by works: the place referred to is ( Genesis 15:6 ) ;

Abraham believed God;
the object of his faith and trust were not his riches, nor his righteousness, but Jehovah, the Son of God, the second person in the Trinity, styled in ( Genesis 15:1 ) , "the Word of the Lord", the essential Word of God, and called his "shield", and "exceeding great reward"; characters which are very applicable to Christ: and this faith of his in the Lord was not a mere assent to the promise of God, but a fiducial act of faith in him; and was not merely concerned with temporal, but with spiritual things, and particularly about Christ the promised seed:

and it was counted to him for righteousness,
the meaning of which is not, that Abraham imputed righteousness to God, or celebrated his righteousness and faithfulness, as some; or that the world reckoned Abraham a righteous person, as others; but that God reckoned him righteous, or imputed it to him for righteousness: and the question is, what the it is which was counted to him for righteousness? and that this is to be understood, (hnmah le) , "concerning faith", as R. Solomon Jarchi says, is out of question; for this is expressly said by the apostle, ( Romans 4:9 ) . The only one is, whether it means the grace of faith by which he believed; or the object of faith on which he believed, and with which his faith was conversant: not the former, for that is not righteousness, nor accounted so; but is distinguished from it, and is that by which a person receives and lays hold on righteousness; besides, whatever may be alleged in favour of the imputation of Abraham's faith to himself for righteousness, it can never be thought to be imputed to others on that account; whereas the very selfsame it is imputed to others also; see ( Romans 4:24 ) ; it remains then that it was the promised seed, the Messiah, and his righteousness, which Abraham, by faith, looked unto, and believed in, that was made unto him righteousness by imputation. Now since so great and good a man as Abraham was not justified by works, but by faith in the righteousness of the Messiah, it follows, that none of his sons, nor any other person whatever, ought to seek for, or expect to be justified in any other way.