Daniel 7:19
I desired to know the truth about the fourth beast that was different from the others. This beast was exceeding terrible. It had teeth made of iron. Its claws were made of copper. It devoured, broke in pieces, and stamped what was left with its feet.
Daniel 7:7
After this I saw more visions in the night. I saw a FOURTH BEAST terrible and powerful, and exceedingly strong! It had great iron teeth. It devoured and broke in pieces, and stamped the residue with its feet. It was different from the beasts that came before it. It had ten horns!
Daniel 2:40-43
The fourth kingdom will be strong as iron, since iron breaks in pieces and subdues all things. It is iron that crushes all these. It will break in pieces and crush.