'Rod of Iron' in the Bible

And he shall shepherd them with a rod of iron, shattering them like earthen vessels (as I myself have received from my Father),

And she gave birth to a son, a man child, who is to shepherd all the nations with a rod of iron; and her child was caught up unto God and unto his throne.

And there issues from his lips a sharp sword with which to smite the nations. He shall shepherd them with a rod of iron. And he treads the winepress of the passion of the anger of Almighty God.