(32) Why does he say, “In the tenth month, on the first day of the month, the heads of the mountains appeared?” (#Ge 8:4). As in numerals the number ten is the extreme bound of the units, being a definitive and perfect number, so too it is the cycle and end of the units, and also the beginning and cycle of the decades, and of infinity of numbers; thus the Creator, on the cessation of the deluge, condescended that the tops of the mountains should appear in the number of the decade, being a definitive and perfect number.
(33) Why was it after forty days that the just man opened the window of the ark? (#Ge 8:5). We must observe carefully that the divine historian uses the same number in speaking of the influx of the deluge and in mentioning the cessation and complete removal of the evil; forsooth on the twenty-seventh day of the seventh month in the six hundredth year of the life of Noah, that is to say in the six hundredth year after his nativity, the deluge began at the spring season; but on the twenty-seventh day of the seventh month, the ark rested on the top of the mountains at the vernal equinox. But it is plain from these circumstances that the deluge became invisible in the six hundred and first year of Noah’s life, again on the seventh month and the twenty-seventh day of it, so that after the lapse of an entire year, it again settled and established the earth as it was at the moment of its destruction, in the spring season, budding forth and covered with verdure and full of all kinds of fruits. But again in a similar manner the overflow of the deluge took place for forty days, the cataracts of heaven being opened and fountains bursting upwards from the lowest depths of the earth; and again a hope of renewal took place at intervals of forty days after a sufficient cessation of the rains, when he opened the window; and again the duration of the permanent deluge lasted for a period of a hundred and fifty days, as also its gradual diminution occupied a period of a hundred and fifty days; so that we may well admire the equality of the arrangement, for the evil increased and ceased according to the same number, like the moon, which from its first rise proceeds in its increase according to an equal number, going onward to its perfect fulness of light, and then again with an equal number in its decrease, returning back to its original state, after having been previously full; and in like manner in the case of divine chastisements, the Creator preserves a regular order, banishing all irregularity from the divine borders.