5. What is signified by the beasts and the birds of heaven, what by the earth and the fishes of the sea. — What by the beasts should we understand, save the duller in sense; what by the birds of heaven, save those who savour of the highest and most sublime things? For of the beasts, that is, of those duller in sense, it is written: Thy animals shall dwell therein (Ps. lxvii, 11). And because those who savour of sublime things fly up amid the words of our Redeemer, it is written: So that the birds of heaven come and dwell in its branches (Matt. xiii, 32). But what by the earth, save those who savour of earthly things? Whence also to the first man, forsaking heavenly things, it was said: Earth thou art, and unto earth shalt thou go (Gen. iii, 19).
What by the fishes of the sea should we take, save the curious of this age? Of whom the Psalmist says: The fishes of the sea, that pass through the paths of the sea (Ps. viii, 9). Who in the great searchings-out of things lie hidden as it were in hidden waves. But what all these things, when questioned, may teach, he adds, saying: