Moses therefore by this Word of the divine blessing makes a glorious distinction between the bodies before created, and these living bodies which were created on the fifth day, because here a new method of generation is instituted. For in this case from living bodies are generated separate kinds of offspring which also live. But this certainly is not the case with trees nor herbs; for unless they be sown anew they bear no fruit, nor does a seed grow simply from a seed, but from a plant. But in the present instance a living body is generated from a living body. This latter operation therefore, that animal bodies should increase and be multiplied from bodies of their own kind, is entirely another and a new work of God. Because a pear-tree does not produce a pear-tree but a pear. But in the latter case, that which a bird produces is a bird. That which a fish generates is a fish. Marvellous indeed and numberless is the multiplication of each species and infinite the fecundity, but it is greatest in marine and aquatic animals. What then is the cause of this wonderful and admirable generation or propagation? The hen lays an egg; she cherishes it until a living body is formed in the egg, which at length the hen hatches. Philosophers allege the cause of all this to be the operation of the sun and the heat of the hen's body. I fully grant all this. But divines speak much nearer the truth, when they affirm that the whole generative process takes place by the effective operation of the Word, here spoken by God, "And God blessed them; and said, be fruitful and multiply." This Word of God's blessing is present in the very body of the hen and of all living creatures; and the heat by which the hen cherishes the egg is essentially and effectively the heat of the Word of God; for without this Word the heat of the sun or of the body would be utterly ineffectual and useless. Wherefore to this admirable part of his creation work God adds his peculiar blessing in order that these living bodies now created on the fifth day might be fruitful. From these circumstances may be seen what this divine blessing is, namely, multiplication. Now when we bless we can effect nothing. All we can do is to pray. But this prayer is inoperative. We cannot effect the things for which we pray. But the blessing of God carries with it actual fruitfulness and multiplication. It is at once effectual. On the contrary the divine curse is non-multiplication and diminution. And the curse is also at once effectual.