Then God blessed them and said, “Be fruitful and multiply and fill the waters of the seas, and let birds multiply on the earth.”
God blessed them by giving them power to procreate and multiply their kind. The waters swarm with vast numbers of these creatures, though consumption of them is great; our word 'fish' itself comes from the Hebrew for multiply and increase.
AI summary
God commanded the waters to swarm with living beings and birds to fly above the earth. The text leaves silent which element produced them, but 'swarm' applies to all creatures that congregate in great numbers and move about together, from the greatest to the least.
AI summary
Commenting on Genesis 1:20-23
And God blessed them, saying, Be fruitful, and multiply, and fill the waters in the seas, and let fowl multiply in the earth. (r) That is, by the virtue of his word he gave power to his creatures to reproduce.