'Rod of Iron' in the Bible

Thou shalt break them with a rod of iron; thou shalt dash them in pieces like a potter's vessel.

(And he shall rule them with a rod of iron; as the vessels of a potter shall they be broken to shivers:) even as I received of my Father.

And she brought forth a male child, who was to rule all nations with a rod of iron: and her child was caught up to God, and to his throne.

And out of his mouth goeth a sharp sword, that with it he should smite the nations: and he shall rule them with a rod of iron: and he treadeth the wine-press of the fierceness and wrath of Almighty God.