I will make thee a new sharp threshing-instrument. Israel is to be more than sustained. Strength is to be given her to take the aggressive, and to subdue her enemies under her. She is to "thresh them" and "beat them small," as with a threshing-instrument.
In the literal sense, no earlier accomplishment of this prophecy can be pointed out than the time of the Maccahean war. Metaphorically, it may be said that Israel began to conquer the world when her literature became known to the Greeks through the expedition of Alexander the Great, and completed her conquest when the Roman empire succumbed to the teaching of Jesus of Nazareth.
Having teeth. Threshing-instruments of the kind described are still in use in Syria and Asia Minor. The corn is spread out on the ground, and the machine, which is sometimes armed with sharp stones, sometimes with saws, is dragged ever it.
The Arabic name is still noreg, a modification of the Hebrew moreg. Thou shalt thresh the mountains … the hills; i.e. "thou shalt subdue proud and mighty foes" (Delitzsch).