The main object of this chapter is to show that the doctrine of justification by faith, which the apostle was defending, was found in the Old Testament. The argument is to be regarded as addressed particularly to a Jew, to show him that no new doctrine was advanced. The argument is derived, first, from the fact that Abraham was so justified, Romans 4:1-5; Secondly, from the fact that the same thing is declared by David Romans 4:6-8.
A question might still be asked, whether this justification was not in consequence of their being circumcised, and thus grew out of conformity to the Law? To answer this, the apostle shows Romans 4:9-12 that Abraham was justified by faith before he was circumcised, and that even his circumcision was in consequence of his being justified by faith, and a public seal or attestation of that fact.
Still further, the apostle shows that if people were to be justified by works, faith would be of no use; and the promises of God would have no effect. The Law works wrath Romans 4:13-14, but the conferring of the favor by faith is demonstration of the highest favor of God Romans 4:16. Abraham, moreover, had evinced a strong faith; he had shown what it was; he was an example to all who should follow. And he had thus shown that as he was justified before circumcision, and "before" the giving of the Law, so the same thing might occur in regard to those who had never been circumcised. In Romans. 2; 3, the apostle had shown that all had failed of keeping the Law, and that there was no other way of justification but by faith. To the salvation of the pagan, the Jew would have strong objections. He supposed that none could be saved but those who had been circumcised, and who were Jews. This objection the apostle meets in this chapter by showing that Abraham was justified in the very way in which he maintained the pagan might be; that Abraham was justified by faith without being circumcised. If the father of the faithful, the ancestor on whom the Jews so much prided themselves, was thus justified, then Paul was advancing no new doctrine in maintaining that the same thing might occur now. He was keeping strictly within the spirit of their religion in maintaining that the Gentile world might also be justified by faith. This is the outline of the reasoning in this chapter. The reasoning is such as a serious Jew must feel and acknowledge. And keeping in mind the main object which the apostle had in it, there will be found little difficulty in its interpretation.

Abraham was justified by faith, and not by the works of the law; for his faith was imputed to him for righteousness, Romans 4:1-5. David also bears testimony to the same doctrine, Romans 4:6-8. Abraham, the father of the Jewish race, was justified by faith, even before he was circumcised; therefore salvation must be of the Gentiles as well as the Jews, Romans 4:9-12. And the promise that all the nations of the earth should be blessed in him, was made to him while he was in an uncircumcised state; and, therefore, if salvation were of the Jews alone, the law, that was given after the promise, would make the promise of no effect, Romans 4:13-17. Description of Abraham's faith, and its effects, Romans 4:18-22. This account is left on record for our salvation, that we might believe on Christ, who was delivered for our offenses, and raised again for our justification, Romans 4:23-25.
The apostle, having proved in the foregoing chapter that neither Jews nor Gentiles have a right to the blessing of God's peculiar kingdom, otherwise than by grace, which is as free for the one as the other, in this chapter advances a new argument to convince the Jew, and to show the believing Gentile, in a clear light, the high value and strong security of the mercies freely bestowed on them in the Gospel; and, at the same time, to display the scheme of Divine providence, as laid in the counsel and will of God. His argument is taken from Abraham's case: Abraham was the father and head of the Jewish nation; he had been a heathen, but God pardoned him, and took him and his posterity into his special covenant, and bestowed upon them many extraordinary blessings above the rest of mankind; and it is evident that Abraham was not justified by any obedience to law, or rule of right action, but, in the only way in which a sinner can be justified, by prerogative or the mercy of the lawgiver. Now, this is the very same way in which the Gospel saves the believing Gentiles, and gives them a part in the blessings of God's covenant. Why then should the Jews oppose the Gentiles? especially as the Gentiles were actually included in the covenant made with Abraham for the promise, Genesis 17:4, stated that he should be the father of many nations: consequently, the covenant being made with Abraham, as the head or father of many nations, all in any nation who stood on the same religious principle with him, were his seed and with him interested in the same covenant. But Abraham stood by faith in the mercy of God pardoning his idolatry; and upon this footing the believing Gentiles stand in the Gospel; and, therefore, they are the seed of Abraham, and included in the covenant and promise made to him.
To all this the apostle knew well it would be objected, that it was not faith alone, that gave Abraham a right to the blessings of the covenant, but his obedience to the law of circumcision; and this, being peculiar to the Jewish nation, gave them an interest in the Abrahamic covenant; and that, consequently, whoever among the Gentiles would be interested in that covenant, ought to embrace Judaism, become circumcised, and thus come under obligation to the whole law. With this very objection the apostle very dexterously introduces his argument, Romans 4:1, Romans 4:2; shows that, according to the Scripture account, Abraham was justified by faith, Romans 4:3-5; explains the nature of that justification, by a quotation out of the Psalm, Romans 4:6-9; proves that Abraham was justified long before he was circumcised, Romans 4:9-11; that the believing Gentiles are his seed to whom the promise belongs, as well as the believing Jews, Romans 4:12-17; and he describes Abraham's faith, in order to explain the faith of the Gospel, Romans 4:17-25. See Dr. Taylor's notes. We may still suppose that the dialogue is carried on between the apostle and the Jew, and it will make the subject still more clear to assign to each his respective part. The Jew asks a single question, which is contained in the first and part of the second verses. And the apostle's answer takes up the rest of the chapter.

INTRODUCTION TO ROMANS 4
The apostle having, in the preceding chapters, proved that there is no justification before God by the works of the law, partly from the depraved state and condition that all men are in by nature, both Jews and Gentiles; and partly from the nature of the law itself, which discovers sin, arraigns men for it, and convicts of it, and pronounces guilty before God for it; as also by showing, that it is by another righteousness, which he describes, that men are justified in the sight of God; proceeds in this to confirm the same by an example; and that which he pitches upon is the most appropriate and pertinent he could have thought of, namely, that of Abraham, the father of the Jews, Romans 4:1, for in whatsoever way he was justified, his sons surely could not imagine but it must be the right way, nor should they seek another: now that Abraham was not justified by works, he proves Romans 4:2, from an absurdity following upon it, that he would have just reason to glory; whereas no man ought to glory before God, but only in the Lord: and by a passage of Scripture, Romans 4:3, to which he appeals, he makes it clearly appear that he was justified by faith, for that says, his faith was counted for righteousness. This case of accounting anything to another for righteousness, is illustrated by two sorts of persons, who have different things accounted to them, and in a different manner; to the worker, the reward is reckoned of debt, and not of grace, Romans 4:4, but to the believer that works not, his faith, as Abraham's was, is counted for righteousness; whence it follows, that not the worker is justified by his works, but the believer by the righteousness of faith; and this is confirmed by a testimony of David in Psalm 32:1, by which the apostle proves the imputation of righteousness without works, in which the happiness of men consists, Romans 4:6, and shows, that this happiness does not belong to circumcised persons only, but to the uncircumcised also; and therefore is not by circumcision, but by faith, Romans 4:9, and which he proves by observing the time when faith was reckoned to Abraham for righteousness; not when he was circumcised, but before, Romans 4:10, the use of which circumcision to him was to assure him, that he should be the father of uncircumcised Gentiles that believed, to whom righteousness should be imputed, as to him when he was uncircumcised, Romans 4:11, who are described by their imitation of his faith, which he had, and exercised before his circumcision, Romans 4:12. And this leads on to a fresh argument, proving justification to be by faith, and not by the works of the law, since the promise made to Abraham, and his seed, was not through the law, but the righteousness of faith; and consequently both his and their justification were not by the one, but by the other, Romans 4:13, or, if otherwise, both the faithfulness of God, and the faith of his people, would be void, and the promise of grace of no effect, Romans 4:14. And this is still further argued from the effect of the law working wrath, which, if justification was by it, it would never do, Romans 4:15. The wisdom and goodness of God in giving faith, and not works, a concern in justification, are observed, Romans 4:16, whereby it appears to be of free grace, faith only being a recipient, and what gives all the glory to God; and also the promise of eternal life through justification by free grace becomes sure to all the spiritual seed; who are distributed into two sorts, the believing Jews under the legal dispensation, and the believing Gentiles, under the Gospel dispensation; of both which Abraham was father; which is confirmed by a testimony out of Genesis 17:4, whose faith is described by the object of it, the omnipotent God that quickens the dead, and calls things that are not, as though they were, Romans 4:17, and by the nature of it, Romans 4:18, believing in hope against hope, resting on the promise of God; and by the strength of it, being not at all weakened by considering, either his own case, or that of his wife's, Romans 4:19, and was so far from being staggered through unbelief at these things, that it was strong in exercise, thereby glorifying God, the object of it, Romans 4:20, nay, it rose up to a plerophory, a full assurance, Romans 4:21, being built upon the power of a promising God; hence, as before observed, his faith was reckoned to him for righteousness, Romans 4:22, And now in the same way that he was justified, all his children, his spiritual seed, are justified, whether they be Jews or Gentiles; for what is said concerning the imputation of the righteousness of faith to him, does not concern him only, Romans 4:23, but all true believers also; whose faith is described by the object of it, him that raised up Christ from the dead, that is, God the Father, Romans 4:24, who is supposed hereby to have been dead, and is represented as the Lord and Saviour of his people; and of whom a further account is given, Romans 4:25, as being delivered into the hands of men, of justice, and of death, for the sins of his people, which he took upon him, and bore, and made satisfaction for, and as being raised again for their justification; so that this is a benefit owing not to the works of men, but to what Christ has done and suffered in the room and stead of his people; which is what the apostle meant to bring this point unto; the blessed effects and consequences of which he relates in the next chapter.

(Romans 4:1-12) The doctrine of justification by faith is shown by the case of Abraham.
(Romans 4:13-22) He received the promise through the righteousness of faith.
(Romans 4:23-25) And we are justified in the same way of believing.

SUMMARY.--Abraham not Justified by Works, but by Faith. His Faith Reckoned for Righteousness. David Describes the same Blessedness. This Blessedness of Forgiveness for Gentiles as well as Jews. Abraham Counted Righteous Before He Was Circumcised. The Promise of a Redeemer and of a Land Made to Abraham Before He Was Circumcised. The Greatness of Abraham's Faith. To All, Whether Jew or Gentile, Righteousness will be Imputed, Who have Abraham's Faith.