“And God blessed them, saying, ‘Be fruitful and multiply and fill the waters in the seas, and let birds multiply on the earth.'”Luther’s Commentary “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…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.” “Thus have we then a sight of the living bodies created on the fifth day. And we have seen that the Word of God, spoken on this day, is still effectual; for fishes are still generated from mere and very water. Hence fish-ponds and lakes still generate fishes. Minnows are generated in fish-ponds, in which there were none before. For I see no likelihood of truth in the trifling arguments of some, who will have it that fishes caught by birds, drop their seed into fish-ponds and lakes, while they are being borne along in the air by their feathered captors; and that such dropped fish-seed afterwards increases and furnishes the ponds. I believe therefore the true and sole cause of all this generation and multiplication of fishes, to be God’s commanding Word to the water on the fifth day of his creation work to bring forth fishes. I believe that this divine Word is still effectual; and that it still works all these things!” Martin Luther. Luther on the Creation: A Critical and Devotional Commentary on Genesis [1-3] (Kindle Locations 2035-2047, 2059-2065).