John Chrysostom, on Rom 1:17

But he who hath become just shall live, not for the present life only, but for that which is to come. And he hints not only this, but also another thing along with this, namely, the brightness and gloriousness of such a life. For since it is possible to be saved, yet not without shame (as many are saved of those, who by the royal humanity are released from punishment), that no one may suspect this upon hearing of safety, he adds also righteousness; and righteousness, not thine own, but that of God; hinting also the abundance of it and the facility. For you do not achieve it by toilings and labors, but you receive it by a gift from above, contributing one thing only from your own store, "believing." Then since his statement did not seem credible, if the adulterer and effeminate person, and robber of graves, and magician, is not only to be suddenly freed from punishment but to become just, and just too with the highest righteousness; he confirms his assertion from the Old Testament. And first with a short sentence, he lays open a vast sea of histories to one who has a capacity for seeing them. For after having said, "from faith to faith." he sends the hearer back to the dispensations of God, which took place thus in the Old Testament, which, when writing to the Hebrews, he explains with his usual great wisdom, showing that both the just and the sinners were justified in that way even then, wherefore also he made mention both of the harlot and of Abraham. But then here, after having just hinted at it (for he was running on to another and a pressing subject), he again confirms what he had said from the Prophets, bringing in Habakkuk before them, crying, and saying, that it is not in the nature of things for him who is to live, to live otherwise save by faith; for "the just," he says, "shall live by faith" (Hab. ii. 4), speaking about the life to come. For since what God giveth transcends reasoning entirely, it is but reason that we need faith. But the man that thinks meanly of it, and is contemptuous and vainglorious, will not effect anything at all. Let heretics hearken to the voice of the Spirit, for such is the nature of reasonings. They are like some labyrinth or puzzles which have no end to them anywhere, and do not let the reason stand upon the rock, and have their very origin in vanity. For being ashamed to allow of faith, and to seem ignorant of heavenly things, they involve themselves in the dust-cloud of countless reasonings. Then oh miserable and painful man, fit object for endless tears, should any one ask thee, how the heaven was made, and how the earth,-and why do I say the heaven and the earth? how thou wert thyself born, how nourished, and how thou grewest, art thou then not ashamed of thine ignorance? But if anything be said about the Only-begotten, dost thou thrust thyself through shame into a pit of destruction, thinking that it is unworthy of thee not to know everything? And yet disputatiousness is an unworthy thing, and so is ill-timed curiosity. And why do I speak of doctrines? for even from the corruption in our present life we have escaped by no other means than through the faith. Thus shone also all those aforetime, thus Abraham, thus Isaac, thus Jacob, thus too the harlot was saved, the one in the Old Testament, and likewise the one in the New. For, "by faith," he says, "the harlot Rahab perished not with them that believed not when she had received the spies." (Heb. xi. 31.) For if she had said to herself, "and how can they that are captives and exiles, and refugees, and live the life of vagabond tribes, get the better of us who have a city, and walls, and towers?" she would have destroyed both herself and them. Which also the forefathers of those who were then saved did suffer. For when, upon the sight of men great and tall, they questioned the manner of victory, they perished, without battle or array, all of them. Seest thou what a pit is that of unbelief! what a wall that of faith! For the one carried down endless thousands, the other not only saved a harlot, but made her the patroness of so numerous a people!