Faith, which believes in the justifier, is the beginning of justification before God. And this faith, when it is justified, is like a root in the soil of the soul, which the rain has watered, so that as it begins to grow by the law of God, branches appear, which bring forth fruit. The root of righteousness does not spring from works; rather, the fruit of works grows from the root of righteousness, viz., by that root of righteousness by which God brings righteousness to the one whom he has accepted apart from works.
This refers to somebody who is bound by sin and who therefore does not do what the law commands. Paul says this because to an ungodly person, that is, to a Gentile, who believes in Christ without doing the works of the law, his faith is reckoned for righteousness just as Abraham’s was. How then can the Jews think that they have been justified by the works of the law in the same way as Abraham, when they see that Abraham was not justified by the works of the law but by faith alone? Therefore there is no need of the law when the ungodly is justified before God by faith alone.
For reflect how great a thing it is to be persuaded and have full confidence that God is able on a sudden not to free a man who has lived in impiety from punishment only, but even to make him just, and to count him worthy of those immortal honors. Do not then suppose that this one is lowered in that it is not reckoned unto the former of grace. For this is the very thing that makes the believer glorious; the fact of his enjoying so great grace, of his displaying so great faith. And note too that the recompense is greater. For to the former a reward is given, to the latter righteousness. Now righteousness is much greater than a reward. For righteousness is a recompense which most fully comprehends several rewards. Therefore after proving this from Abraham, he introduces David also as giving his suffrage in favor of the statement made. What then does David say? And whom does he pronounce blessed? Is it him that triumphs in works, or him that has enjoyed grace? Him that has obtained pardon and a gift? And when I speak of blessedness, I mean the chiefest of all good things; for as righteousness is greater than a reward, so is blessedness greater than righteousness. Having then shown that the righteousness is better, not owing to Abraham's having received it only but also from reasonings (for he has whereof to boast, he says, before God ); he again uses another mode of showing that it is more dignified, by bringing David in to give his suffrage this way. For he also, he says, pronounces him blessed who is so made righteous, saying, (Romans 4:7)
Think how great a thing it is to be persuaded and have complete confidence that God is able not only to set an ungodly man free from punishment but also to make him righteous and count him worthy to receive these immortal honors.… This is what makes a believer glorious—the fact that he enjoys so great a grace and displays such great faith. Note too that the recompense is greater. For the one who works receives his reward, but the one who believes is made righteous. Righteousness is much greater than a reward, because it is a recompense which includes many rewards.
When an ungodly person is converted, God justifies him by faith alone, not for good works which he does not have. On that basis he would have been punished for his ungodly works. But note that Paul does not say one who remains in sin is justified by faith but rather the ungodly, i.e., one who has just come to believe.
God makes the ungodly man godly, in order that he might persevere in this godliness and righteousness. For a man is justified in order that he might be just, not so that he might think it is all right to go on sinning.
[AD 253] Origen of Alexandria on Romans 4:5