Its underparts ¹  are the sharp points of potsherds, it leaves its mark in the mud like a threshing sledge. ² 

Certainly ¹  caraway seed is not threshed with a sledge, nor is the wheel of a cart rolled over cumin seed. ²  Certainly caraway seed is beaten with a stick, and cumin seed with a flail.

“Look, I am making you like ¹  a sharp threshing sledge, new and double-edged. ²  You will thresh the mountains and crush them; you will make the hills like straw. ³