John Calvin Commentary Isaiah 19:8

"And the fishers shall lament, and all they that cast angle into the Nile shall mourn, and they that spread nets upon the waters shall languish." — Isaiah 19:8 (ASV)

And the fishers shall mourn. Isaiah still keeps in view the condition of Egypt. We have previously mentioned that the prophets used those figures of speech where, when any country is mentioned, they primarily name those things in which that country abounds and for which it is celebrated. Thus, when a vine-bearing country is spoken of, they mention vines; if it abounds in gold, they speak of gold; and if it abounds in silver, they speak of silver. Accordingly, when he speaks of Egypt, which was well-watered and had an abundance of streams, he mentions fishing.

They who spread a net on the face of the waters shall languish. Some translate the word אמללו, (ămlālū,) “they shall be cut off,” but the more correct rendering is, “they shall be weakened;” for this corresponds to the mourning and lamentation that was previously mentioned. Now, we know that in that country there were many fishers, and that these formed a large part of the wealth of Egypt. When fishers were taken away—of whom there were vast numbers among the Egyptians, and who constituted a chief part of their wealth—they must have been weakened. Now, if the nation is deprived of that which is its ordinary food, great poverty will follow. He therefore describes an astonishing change that will come upon the whole country.