John Calvin Commentary Jeremiah 48:17

"All ye that are round about him, bemoan him, and all ye that know his name; say, How is the strong staff broken, the beautiful rod!" — Jeremiah 48:17 (ASV)

The Prophet indeed seems to urge all neighbors to sympathy. However, we have stated why he did this. His purpose was not to show that the Moabites deserved pity, so that their neighbors should have grieved with them in their calamities. Rather, by this figurative way of speaking, he exaggerated the severity of the evils that were soon to happen to the Moabites, as if he had said, “This judgment of God will be so dreadful as to make all their neighbors tremble; all who had previously known the state of the people of Moab will be struck with such terror as will make them groan and mourn with them.” In short, the Prophet aimed only to show that God’s vengeance on the Moabites would be no less severe and dreadful than it had been on the ten tribes, and as it would be on the tribe of Judah.

Say ye, he says, how is the staff broken? He introduces all their neighbors here as astonished. For the same purpose, other things are mentioned—specifically to show that the calamity of Moab would be considered a prodigy, because the people thought them unassailable, and no one had ever dared to attempt anything against their land. This, then, was why the Prophet, speaking as if astonished and in the voice of all nations, asks here: How has it happened that the staff is broken? and the beautiful rod? These metaphorical words refer to the royal dignity and the condition of the entire people.