(Saba'a) 34 : 11
أَنِ اعْمَلْ سَابِغَاتٍ وَقَدِّرْ فِي السَّرْدِ ۖ وَاعْمَلُوا صَالِحًا ۖ إِنِّي بِمَا تَعْمَلُونَ بَصِيرٌ
And make full-length Armor perfectly balancing its links; you do righteous deeds, indeed I am watching whatever you do.
Making the war weapons by melting the iron was started during the period of Messenger Dawood. See explanation 5: 48; 21: 78-80.