“And rain fell upon the earth,” says Moses, “forty days and forty nights.” Behold for you why Moses said that the cataracts of heaven were opened: namely, to indicate that an immense force of waters was poured from heaven onto the lands — which the continuous and most dense rain of forty days plainly declares. And Cajetan well notes in this place that what was said by Moses about the rain of forty days is to be understood likewise of the eruption of waters onto the lands from the fountains of the abyss: for in equal time the water both flowed down from heaven, and gushed and burst forth from the e[arth]…¹

…both flowed down from heaven, and gushed and burst forth from the earth. But from these words four doubts arise. The first: Why did Moses distinctly name days and nights? For it would have been enough to say “forty days.” Did he speak thus lest, if he had said precisely “forty days,” someone might perhaps think that those were artificial days [daytime], and that it rained indeed by day but not by night? He said, therefore, “days and nights,” to signify the natural day, which consists of twenty-four hours, and that that rain fell continuously both by day and by night. But because both Moses elsewhere often in scripture, and in this very chapter a little below, sets down the name “day” precisely to signify the natural day, it could be said, not without probability, that this distinct mention of days and nights is sometimes employed in the sacred writings where something very notable and admirable is related: and that this is done for emphasis — namely, both for the greater heightening of the matter narrated, and for the admiration of the readers and hearers.²

For example: it is beyond human power and belief that any mortal should have used no food or drink for forty days; yet, when divine Scripture narrates this of Moses, of Elijah, of our Lord the Savior, it says that they fasted forty days and forty nights. Similarly, then, because it was very wonderful that it rained continuously for forty whole days, therefore Moses said that it rained forty days and forty nights.³

The second doubt. Whence did Noah have it ascertained and known that those forty days and forty nights had passed during which that rain fell? For, shut up in the Ark, he could see neither the presence nor the absence of the Sun; nor, if he had been outside the Ark at that time, could he have seen the Sun, the heaven being on every side overspread with the densest vapors and, as it were, blinded. Did Noah — or Moses, who wrote this history — know this by some singular revelation of God? Or did Noah have within the Ark some clock (horologium) which, by its motion and sound, indicated each and every hour of the day and night?⁴

The third doubt. Whence was there so great a supply of vapors, from which the rain of forty days might be generated? Is it fitting to think that a great deal of the earth at that time was thinned and resolved into aqueous vapors, and that all the vapors which were in the air were then changed into water? And not only this, but besides it may be credible that a great part of the air was changed into rain-water: for since the flood covered the whole earth so deeply that it surpassed the highest mountains by fifteen cubits, it must be believed that the air which before occupied all that space around the earth (which was afterward filled with waters) was turned into water.⁵

The fourth doubt. Which was the more principal cause of the flood: the terrestrial water — whether bursting from the fountains of the abyss, or that which was poured out from the sea — or the rain that flowed down from heaven for forty days? For my part, I would believe that the chief cause of the flood was in the rain of forty days. For neither could the wa[ter]…⁶

…the water, whether leaping out from subterranean places, or flowing over the earth, or inundating the earth from the surging sea, could grow and swell so much, and ascend to so great a height, as to surpass the peaks of all the mountains by fifteen cubits: since that height was, by a very great interval, greater than the origin of all terrestrial waters, and than any swelling and heaping-up of the sea. That excess of the flood above all the mountains, therefore, could come about from nothing else than the celestial rain: for the origin of this was higher than the place to which the flood reached. For the height of the flood, although it was very great, was nevertheless below the middle region of the air, where rain is generated.⁷

Nor did that production and extension of the rain over forty days fail to furnish a notable argument of the divine longsuffering and kindness, awaiting and inciting those men to penance by so slow a delay of vengeance and destruction. Hear Chrysostom: “Now,” he says, “that the flood was brought on over forty days — this very thing too is the greatest kind of goodness. For, on account of his great mercy, he wished that even some of them, being chastened, might escape that general destruction, when they saw their neighbors perishing before their eyes and the common ruin threatening them. For it is likely that on the first day of the flood a good part of the men perished, and on the second day another, and likewise on the third and fourth and the rest; and thus he prolonged it over forty days, that he might take from them every pretext of defense. For if he had willed and commanded, he could in one moment have destroyed all things by a flood; but in his mercy he used so great a prolongation of days.” So St. Chrysostom.⁸

And so, what is reported in the sacred writings about the inhabitants of the region of Canaan (who being expelled, God gave that region to the Hebrews), the same can most truly be said of those who perished in the flood. For thus it is written in the book of Wisdom: “Not because thou wast unable to subject the impious to the just in battle, or by cruel beasts, or with a harsh word to exterminate them at once; but, judging by degrees, thou gavest place for penance, not being ignorant that their nation is wicked, and their malice natural, and that their thought could never be changed: and thou gavest pardon to their sins. And thou hast taught thy people, by such works, that the just man ought to be also humane; and thou hast made thy children of good hope, because, in judging, thou givest place in [their] sins for penance. For if thou hast tormented with such attention the enemies of thy servants, as deserving death, giving time and place by which they might be changed from their malice,” etc.⁹