Then God blessed them and said, “Be fruitful and multiply and fill the waters of the seas, and let birds multiply on the earth.”
22. And God blessed them What is the force of this benediction he soon declares. For God does not, after the manner of men, pray that we may be blessed; but, by the bare intimation of his purpose, effects what men seek by earnest entreaty. He therefore blesses his creatures when he commands them to increase and grow; that is, he infuses into them fecundity by his word.
Each day, hitherto, has produced very noble and excellent beings, which we can never sufficiently admire; but we do not read of the creation of any living creature till the fifth day, of which these verses give us an account.
Commenting on Genesis 1:20-23
And God blessed them,.... With a power to procreate their kind, and continue their species, as it is interpreted in the next clause, saying, be fruitful, and multiply, and fill the waters in the seas: and these creatures do multiply exceedingly, and vast quantities there are of them in the mighty waters, though the consumption of some sorts of them is very great.