'Bronze' in the Bible

"I will go before you and level mountains. Bronze doors I will shatter and iron bars I will hack through.

I did this because I know how stubborn you are. Your neck muscles are like iron and your forehead like bronze.

Instead of bronze, I will bring you gold, instead of iron, I will bring you silver, instead of wood, I will bring you bronze, instead of stones, I will bring you iron. I will make prosperity your overseer, and vindication your sovereign ruler.