Iron was not widely used during this part of the Bronze Age. Only a few cultures knew how to smelt iron (heat the ore to remove metal) and shape it into tools and weapons (see 1 Samuel 13:19–21).
Later, Israel learned to use this much stronger metal. They were able to mine it and make tools and weapons from it (see Joshua 17:16–18; 1 Kings 6:7; 2 Kings 6:5; 1 Chronicles 22:3).