Musannaf Ibn Abi Shayba 16:960

Abu Bakr narrated to us, he said: Isa ibn Yunus narrated to us, from al-Awza’i, from Ibn Habib al-Muharibi, from Abu Umamah al-Bahili, the companion of the Messenger of Allah (may Allah bless him and grant him peace), who said: "Indeed, the conquests were opened by peoples whose sword ornaments were neither gold nor silver; rather, their ornaments were leather straps, lead, and iron."