Albert Barnes Commentary Jeremiah 50:38

"A drought is upon her waters, and they shall be dried up; for it is a land of graven images, and they are mad over idols." — Jeremiah 50:38 (ASV)

A drought - Rather, “a sword,” that is, military skill and forethought.

They are mad upon their idols - Omit their. The word for idols, literally “terrors” (Psalms 88:16), is used in this place alone for objects of worship. Probably it refers to those monstrous forms invented as representations of their deities.