"You use steel to sharpen steel, and one friend sharpens another. "
- Proverbs 27:17
"He teacheth my hands to war, so that a bow of steel is broken by mine arms."
-Psalms 18:34
"Is my strength the strength of stones? Or is my flesh of steel?"
-Job 6:12
"They had breast-plates which seemed to be made of steel; and the noise caused by their wings was like that of a vast number of horses and chariots hurrying into battle."
-Revelation 9:9