Shared ground
Isaiah 19:16–17 portrays a coming time (“in that day”) when Egypt’s response is not confidence but panic. The passage explicitly links that fear to Yahweh’s initiative: he is pictured as raising and shaking his hand over them, and he is repeatedly named “Yahweh of Hosts” as the source of the threat.
The text also explicitly says that “the land of Judah” becomes a terror to Egypt, so much so that even mentioning Judah triggers fear. The passage explains this reaction not by Judah’s natural strength, but by “the purpose of Yahweh of Hosts.”
Where interpretation differs
1) What “like women” is doing in v.16. Most agree it communicates vulnerability and loss of nerve. Some readers take it mainly as a conventional ancient comparison for being unready to fight; others hear it as a broader, demeaning insult. Either way, the main point in context is Egypt’s collapse into dread.
2) What “against it” refers to in v.17. Some read it as Yahweh’s purpose against Egypt (the nearest idea in the verse’s flow). Others think it could point back to Judah or to the situation involving Judah. The practical outcome is similar in v.17: Egyptians fear Judah because Yahweh has decided on a plan tied to Judah that threatens Egypt.
3) How literal the “shaking hand” image is. Many take it as figurative for imminent action and judgment; some also connect it to concrete historical events (military movements, imperial pressure) through which Yahweh’s purpose is carried out.
Why the disagreement exists
These verses use compressed poetic images (“shaking hand,” “terror,” “purpose”) rather than spelling out the mechanism. Also, the pronoun “it” at the end of v.17 can be read more than one way in English, and the Hebrew wording can be discussed similarly.
What this passage clearly contributes
The passage reinforces Isaiah’s larger claim that international outcomes are not finally decided by alliances or reputations but by Yahweh’s “purpose.” Egypt—often imagined as a stabilizing power—can become psychologically undone when Yahweh “raises his hand.” Judah’s significance here is not that it dominates Egypt by itself, but that it becomes a focal point of fear because Yahweh has attached his plan to it (compare the repeated divine title in Isaiah 19:16 and Isaiah 19:17).