'Iron' in the Bible

The Lord was with Judah, and [the tribe of] Judah took possession of the hill country, but they could not dispossess and drive out those inhabiting the valley because they had iron chariots.

Then the Israelites cried out to the Lord [for help], for Jabin had nine hundred iron chariots and had oppressed and tormented the sons of Israel severely for twenty years.

Sisera called together all his chariots, nine hundred iron chariots, and all the people who were with him, from Harosheth-hagoyim to the river Kishon.