Who believe on him, etc. I have already reminded you of the design of those periphrastic expressions: Paul introduced them, that he might, according to what the passages may require, describe in various ways the real character of faith -- of which the resurrection of Christ is not the smallest part; for it is the ground of our hope as to eternal life. Had he said only, that we believe in God, it could not have been so readily learnt how this could serve to obtain righteousness; but when Christ comes forth and presents to us in his own resurrection a sure pledge of life, it then appears evident from what fountain the imputation of righteousness flows.

But for us also - For our use; (compare Romans 15:4; 1-Corinthians 10:11), that we might have an example of the way in which people may be accepted of God. It is recorded for our encouragement and imitation, to show that we may in a similar manner be accepted and saved.
If we believe on him - Abraham showed his faith in God by believing just what God revealed to him. This was his faith, and it might be as strong and implicit as could be exercised under the fullest revelation. Faith, now, is belief in God just so far as he has revealed his will to us. It is therefore the same in principle, though it may have reference to different objects. It is confidence in the same God, according to what we know of his will. Abraham showed his faith mainly in confiding in the promises of God respecting a numerous posterity. This was the leading truth made known to him, and this he believed.
(The promise made to Abraham was, "in thy seed shall all nations of the earth be blessed," on which we have the following inspired commentary: "And the scriptures foreseeing that God would justify the pagan through faith, preached before the gospel unto Abraham, saying, In thee shall all nations be blessed," Galatians 3:8. It would seem, then, that this promise, like that made immediately after the fall, contained the very germ and principles of the gospel. So that after all there is not so great difference between the object of Abraham's faith, and that of ours. Indeed the object in both cases is manifestly the same.)
The main or leading truths that God has made known to us are, that he has given his Son to die; that he has raised him up; and that through him he is ready to pardon. To put confidence in these truths is to believe now. Doing this, we believe in the same God that Abraham did; we evince the same spirit; and thus show that we are the friends of the same God, and may be treated in the same manner. This is faith under the gospel (compare the notes at Mark 16:16), and shows that the faith of Abraham and of all true believers is substantially the same, and is varied only by the difference of the truths made known.

But for us also - The mention of this circumstance has a much more extensive design than merely to honor Abraham. It is recorded as the model, according to which God will save both Jews and Gentiles: indeed there can be no other way of salvation; as all have sinned, all must either be saved by faith through Christ Jesus, or finally perish. If God, therefore, will our salvation, it must be by faith; and faith contemplates his promise, and his promise comprehends the Son of his love.

But for us also, to whom it shall be imputed,.... What was written in the books of the Old Testament, was not written merely on account of them who are the subjects thereof, but for the use, learning, instruction and profit of saints under the New Testament dispensation; and particularly this concerning the pulsation of Abraham's faith for righteousness, or of the imputation of the righteousness of faith unto him for justification; which was not Abraham's faith, but that "righteousness" which his faith looked to, and laid hold on: see Romans 4:12; for Abraham's faith itself could never be reckoned for righteousness to another, nor indeed was it to himself; but such as believe as Abraham did, they have the same righteousness imputed to them as he had; and truly of the same kind is the faith of Abraham, who believed in "God that quickeneth the dead", Romans 4:17; and that of ours:
if, or "seeing"
we believe on him that raised up Jesus our Lord from the dead; which descriptive of the faith of New Testament believers, and of the object of it; see Romans 10:9; and which object of faith is further described in Romans 4:25.

to whom it shall be imputed, if we believe in him that raised up Jesus our Lord from the dead--in Him that hath done this, even as Abraham believed that God would raise up a seed in whom all nations should be blessed.

But on ours also - To establish us in seeking justification by faith, and not by works; and to afford a full answer to those who say that, " to be justified by works means only, by Judaism; to be justified by faith means, by embracing Christianity, that is, the system of doctrines so called." Sure it is that Abraham could not in this sense be justified either by faith or by works; and equally sure that David (taking the words thus) was justified by works, and not by faith. Who raised up Jesus from the dead - As he did in a manner both Abraham and Sarah. If we believe on him who raised up Jesus - God the Father therefore is the proper object of justifying faith. It is observable, that St. Paul here, in speaking both of our faith and of the faith of Abraham, puts a part for the whole. And he mentions that part, with regard to Abraham, which would naturally affect the Jews most.