Rom. 4:13. For the promise to Abraham, or to his seed, that he should be heir of the world, was not through the law, but through the righteousness of faith.
Rom. 4:14. If those who rely on the law are heirs, then faith is in vain and the promise is of no effect.
The Apostle has already proven that justification comes not by the law, but by faith. Now he proves that Abraham also received the promise not by the law, but by righteous faith. What then is the "promise"? "To be heir of the world," that is, that in him all the nations of the entire world would be blessed. For if the inheritance, he says, is given by the law, then "faith is made void," that is, it turns out to be vain and useless. For who would concern himself with faith if the promise of the inheritance were given by the law? But the state of affairs is not so. Abraham inherited the promise not by the law (for where was the law then?), but by faith, as it is written: "Abraham believed" (Gen. 15:6).
Rom. 4:15. For the law produces wrath; for where there is no law, neither is there transgression.
Now he proves in what way "the promise is made of none effect." With the law, he says, transgression is joined, and transgression of the law produces wrath and subjects one to the curse and punishment. How then, one asks, is the one guilty of transgression worthy to inherit?
Rom. 4:16. Therefore it is of faith, that it might be by grace; so that the promise might be sure to all, not only to those who are of the law, but also to those who are of the faith of the descendants of Abraham, who is the father of us all:
Rom. 4:17. (as it is written: I have made you a father of many nations) before God, Whom he believed.
Since the law produces wrath, it is said that Abraham was justified and became an heir by faith, so that everything would be by grace. And why is grace necessary? "So that the promise would be firm." For grace, unlike the law, has no transgression, so that what is given would not be uncertain. Since everything comes by grace and the mercy of God, what is given is justly firm "for all of us," that is, for all believers, not only for those who are "of the law," that is, circumcised, but also for those who are uncircumcised, who are the seed of Abraham, born "by faith." Therefore whoever does not have faith is not the seed of Abraham, "who is the father of us all," that is, of believers, as it is written: "I have made you a father of many nations."
The meaning is as follows: Abraham is the father of all "before God," that is, in a manner similar to God. As God is the Father of all, so also is Abraham, not by natural kinship, but by the bond of faith. He added "whom he believed" in order to show that Abraham also received a reward for his faith—to be the father of all. Therefore, if you, O Jew, do not acknowledge that Abraham is the father of all, then you have diminished the honor which he received through faith.
Rom. 4:17. Giving life to the dead and calling the non-existent as existent.
Now he repeats what was said above, that is, that Abraham believed that God could not only revive his deadened flesh, such as his was, but also make it fruitful; which is why he now says: "who gives life to the dead." And the words "who calls those things which do not exist as though they did" he added in order to show that it is not impossible for God to make those who are not children of Abraham into his children. He did not say, however, "who brings into being that which does not exist," but "who calls." How easy it is for us to name something that exists, just as easy it is for God to bring into being that which does not exist.
Rom. 4:18. He, beyond hope, believed with hope, through which he became the father of many nations.
Do not think, he says, that Abraham was honored without merit. For how could this be, when beyond human hope he believed with divine hope that he would become the father of many nations — not those who descended from Ishmael (for they descended from Abraham not by faith, but by nature), but those who are like him in faith?
Rom. 4:18. According to what was said: "so numerous shall your seed be."
Rom. 4:19. And not being weak in faith, he did not consider that his own body was already dead, being about a hundred years old, and the deadness of Sarah's womb;
Rom. 4:20. He did not waver at the promise of God through unbelief, but was strengthened in faith, giving glory to God.
Rom. 4:21. Being fully convinced that He is able also to fulfill what He has promised.
Having said that Abraham beyond human hope believed with the hope of God, he now proves this, saying that Abraham was told: "I will multiply your seed as the stars of heaven and as the sand" (Gen. 15:5, 22:17); yet he did not weaken in faith, but, remaining firm in it, paid no attention either to his own body, already deadened by time, or to the double deadening of Sarah's womb (for her womb was deadened both by old age and by barrenness), and did not fall into perplexity, that is, he did not doubt in the least, was not shaken in thought, but "remained firm in faith."
Note how he proves that the believer has need of great strength. Many disparaged faith as a matter requiring no labor, while they exalted works as requiring sweat and strength. But the apostle says that the believer has need of a great and mighty soul, so as to repel the suggestions of unbelief, just as Abraham was strong in faith. And how was Abraham strong in faith? "Giving glory to God," that is, not believing through human reasoning, but thinking within himself thoughts worthy of the glory of God, and being fully persuaded that God is able to do the impossible; for in this consists the glory of God. He said "almost a hundred years old" approximately, because at that time Abraham was not yet a full hundred years old.
Rom. 4:22. Therefore it was also imputed to him for righteousness.
Rom. 4:23. Now it was not written for his sake alone, that it was imputed to him,
Rom. 4:24. But also with respect to us; it shall be imputed to us as well, who believe in Him Who raised from the dead Jesus Christ, our Lord,
Rom. 4:25. Who was delivered for our sins and rose for our justification.
The Apostle said much in praise of Abraham, but someone might object: what is that to us? Therefore he states that it was written for us as well, that faith will be reckoned as righteousness for us too, if only we have it, believing in Him Who raised Jesus. If you doubt how you can be justified, then picture in your soul Jesus, Who blotted out all your sins, Who died not for His own sin, but for the sin of the world. Since He died without having sin, He justly rose again. For how could He Who had no sin be held in Hades? Thus, He died and rose again precisely so that He might both free us from sins and make us righteous. Therefore, just as Abraham believed that his already deadened body would become fruitful, so you too believe that Jesus died and rose again, and it will be reckoned to you as righteousness, just as it was to your forefather Abraham.