35. But what is this; what kind of mystery is this? Behold, O Lord, thou dost bless men in order that they may be "fruitful and multiply, and replenish the earth." In this art thou not making a sign to us that we may understand something [allegorically]? Why didst thou not also bless the light, which thou calledst "the day," nor the firmament of heaven, nor the lights, nor the stars, nor the earth, nor the sea? I might reply, O our God, that thou in creating us after thy own image--I might reply that thou didst will to bestow this gift of blessing upon man alone, if thou hadst not similarly blessed the fishes and the whales, so that they too should be fruitful and multiply and replenish the waters of the sea; and also the fowls, so that they should be multiplied on the earth. In like fashion, I might say that this blessing properly belonged only to such creatures as are propagated from their own kind, if I could find it given also as a blessing to trees, and plants, and the beasts of the earth. But this "increase and multiply" was not said to plants or trees or beasts or serpents--although all of these, along with fishes and birds and men, do actually increase by propagation and so preserve their species.
36. What, then, shall I say, O Truth, O my Life: that it was idly and vainly said? Surely not this, O Father of piety; far be it from a servant of thy Word to say anything like this! But if I do not understand what thou meanest by that phrase, let those who are better than I--that is, those more intelligent than I--interpret it better, in the degree that thou hast given each of us the ability to understand.
But let also my confession be pleasing in thy eyes, for I confess to thee that I believe, O Lord, that thou hast not spoken thus in vain. Nor will I be silent as to what my reading has suggested to me. For it is valid, and I do not see anything to prevent me from thus interpreting the figurative sayings in thy books. For I know that a thing that is understood in only one way in the mind may be expressed in many different ways by the body; and I know that a thing that has only one manner of expression through the body may be understood in the mind in many different ways. For consider this single example--the love of God and of our neighbor--by how many different mysteries and countless languages, and, in each language, by how many different ways of speaking, this is signified corporeally! In similar fashion, the "young fish" in "the waters" increase and multiply. On the other hand, whoever you are who reads this, observe and behold what Scripture declares, and how the voice pronounces it in only one way, "In the beginning God created heaven and earth." Is this not understood in many different ways by different kinds of true interpretations which do not involve the deceit of error? Thus the offspring of men are fruitful and do multiply.
37. If, then, we consider the nature of things, in their strictly literal sense, and not allegorically, the phrase, "Be fruitful and multiply," applies to all things that are begotten by seed. But if we treat these words figuratively, as I judge that the Scripture intended them to be--since it cannot be for nothing that this blessing is attributed only to the offspring of marine life and man--then we discover that the characteristic of fecundity belongs also to the spiritual and physical creations (which are signified by "heaven and earth"), and also in righteous and unrighteous souls (which are signified by "light and darkness") and in the sacred writers through whom the law is uttered (who are signified by "the firmament established between the waters and the waters"); and in the earthly commonwealth still steeped in their bitterness (which is signified by "the sea"); and in the zeal of holy souls (signified by "the dry land"); and the works of mercy done in this present life (signified by "the seed-bearing herbs and fruit-bearing trees"); and in spiritual gifts which shine out for our edification (signified by "the lights of heaven"); and to human affections ruled by temperance (signified by "the living soul"). In all these instances we meet with multiplicity and fertility and increase; but the particular way in which "Be fruitful and multiply" can be exemplified differs widely. Thus a single category may include many things, and we cannot discover them except through their signs displayed corporeally and by the things being excogitated by the mind.
We thus interpret the phrase, "The generation of the waters," as referring to the corporeally expressed signs [of fecundity], since they are made necessary by the degree of our involvement in the flesh. But the power of human generation refers to the process of mental conception; this we see in the fruitfulness of reason. Therefore, we believe that to both of these two kinds it has been said by thee, O Lord, "Be fruitful and multiply." In this blessing, I recognize that thou hast granted us the faculty and power not only to express what we understand by a single idea in many different ways but also to understand in many ways what we find expressed obscurely in a single statement. Thus the waters of the sea are replenished, and their waves are symbols of diverse meanings. And thus also the earth is also replenished with human offspring. Its dryness is the symbol of its thirst for truth, and of the fact that reason rules over it.