Al-Hadid · 57:25

25. Verily I sent My messengers with clear evidence and manifest proof, and sent down books with them and the balance, so that people would uphold justice. I also sent down iron in which there is great strength; armour is made from it, together with it having many other benefits for the people in their manufacturing and handicrafts. And also because Allah can make it obvious to the people who it is that supports Him and His messengers in secret. Indeed, Allah is Strong and Almighty; nothing can overcome His decree nor is He incapable of doing anything.