John Gill Commentary Exodus 1:7

"And the children of Israel were fruitful, and increased abundantly, and multiplied, and waxed exceeding mighty; and the land was filled with them." — Exodus 1:7 (ASV)

And the children of Israel were fruitful
In their offspring; became like fruitful trees, as the word signifies:

and increased abundantly ;
like creeping things, or rather like fishes, which increase very much, see (Genesis 1:20)

and multiplied ;
became very numerous, whereby the promises made to Abraham, Isaac, and Jacob, were fulfilled:

and waxed exceeding mighty ;
were hale, and strong, of good constitutions, able bodied men, and so more dreaded by the Egyptians: a heap of words is here used to express the vast increase of the people of Israel in Egypt:

and the land was filled with them ;
not the whole land of Egypt, but the land of Goshen: at first they were seated in a village in that country, but now they were spread throughout the towns and cities in it.