(Verset 5 et suiv.) And the sea water will dry up, and the river will be deserted and dried up, and the rivers will fail, and the streams of the embankments will be thin and dry up. The reed and the rush will wither, the bed of the river will be exposed from its source, and all irrigated crops will dry up. It will dry up and cease to exist. And the fishermen will mourn, and all those who cast a hook into the river and spread a net over the surface of the water, and they will dry up. And those who work with linen will be confused, weaving and creating delicate fabrics, and their irrigated fields will become dry, all those who make ponds to catch fish. Foolish princes of Tanis, wise counselors gave Pharaoh foolish advice. When a strong and harsh king shall have dominion over Egypt, all learning and beauty of secular eloquence shall wither, and the very source of all rivers, the devil from whom all lies originate, shall cause devastation: so that other rivers and streams, which were filled by the turbid waters of the Nile, shall fail. Even the reed and the rush shall dry up from excessive drought. They made paper from the papyrus reed, which grows in the Greek language, and added their own green ink, which is not found in Hebrew. When I asked the scholars what this meant, I heard that in the Egyptian language, this word refers to everything that grows in the green marsh. The reed, according to metaphor, is a hollow speech, having nothing solid in itself. And the papyrus, while it appears to have a core and is not hollow, is still fragile and quickly withers. Moreover, all the rivers, when the source of the rivers dries up, will also dry up, and whatever was previously irrigated by the waters of Egypt will be dried up, so that the fishermen of Egypt, who are strongly opposed to the fishermen of the Lord, may mourn, and those who cast a hook into the river and spread a net over the surface of the water may lament. They deceive each individual by casting a hook into the muddy waters. But those who deceive many together, so that they speak openly in the synagogues of Satan and lead away the flocks of the people, they cast a net over the Egyptian waters. Even those who worked with linen to make the priests' garments will be confused; twisting and weaving it, which properly belongs to the art of dialectics. For 'subtilibus', the Septuagint translates it as 'byssus', which is also used for the priests' garments. And what follows: 'And its ponds will be stagnant, all those who made fish traps, this signifies that all the traps of the Egyptian fishermen will be destroyed and perish. For the gaps that were made to catch fish, as we have interpreted according to sense, both in Hebrew and in all the interpreters, in the place of the fish, souls are placed, so that we are drawn from the history to the tropology, namely that these fishermen, who made the gaps and pits, did so in order to deceive souls in them. It should be noted that for the gaps the LXX translated ζύθον, which is a type of drink made from grains and water, and is commonly called sabaium in the provinces of Dalmatia and Pannonia in both the native and barbaric language. The Egyptians use this mainly so that they do not attribute pure water to those who drink, but rather turbid water, and similar to mixed feces, so that through this kind of potion the doctrine of heretical depravity is shown. Then the princes of Taneos will be fools, which is interpreted as a humble command. For all heretics teach humility contrary to exaltation, and they bring down to the depths, and they are the princes of humble and abject command. Also, the counselors of Pharaoh, who is the king of Egypt, and rightly a scatterer, and divided, and separated into various parts, are described as foolish for giving counsel when the Lord has scattered the wisdom of the wise, and has rejected the understanding of the prudent (1 Corinthians 1).
(Verses 5-7) And the water of the sea shall dry up, and the river shall be desolate and dry, and the streams shall diminish and dry up the water-courses. The reed and the rush shall wither, the channel of the river shall be laid bare and all the irrigated seed shall dry up, wither, and not exist. It is natural that when captivity comes through the anger of God, his wrath shall be followed by pestilence, and all the elements shall rage against those who offend God. Where it is written in another Prophet (Jer. XII), 'And the birds in the air fail, and the fishes in the waters, so that all things are taken away from human use.' We say this if we want to take the dryness of the Nile river and its streams simply. But if we take it as a metaphor: in the river, we understand the kingdom, and in its streams, the leaders; and in the greenness, and the reed, and the papyrus, all the abundance of Egypt, so that through these things, the wealth of Egypt is described, of which Egypt is most fertile. Let us read Ezekiel, where the king Pharaoh is described as a great dragon dwelling in the rivers, and says: The river is mine, and I have made myself. And it is heard: I will put a bit in your jaws, and I will stick the fish of your rivers to your scales, and I will draw you out from the midst of your rivers, and all your fish will cling to your scales, and I will cast you into the desert (Ezek. XXIX, 3, 4). However, in the coming of Christ, all these things are to be understood figuratively, according to what we read above: The Lord will make the sea of Egypt a desert. And again: the Lord will stretch out His hand over the violent river of Egypt, and He will strike it in seven valleys, so that it can be crossed by foot with shoes on. This means that all the errors of the Egyptian waters and the sorceries with which they deceived the subject peoples will be dried up by the coming of Christ. And when it says that the water from the sea will dry up, we can understand it in a historical sense, not that the great sea is meant, but rather the lake of Mareotis, because Scripture calls all gatherings of water seas. Exaggerated statements can also be understood. And what follows: The channel of the river will be exposed from its source, showing that the river and the spring dry up together.
[AD 420] Jerome on Isaiah 19:5-11