Musnad Ahmad 1313:3

Yazid ibn Harun narrated to us, he said: Sharik informed us, from Abd al-Aziz ibn Rufay, from Umayyah ibn Safwan ibn Umayyah, from his father: That the Messenger of Allah, peace and blessings of Allah be upon him, borrowed coats of mail from him on the day of Hunayn. He said: "Is it by force, O Muhammad?" He said: "Rather, it is a guaranteed loan." He said: So some of them were lost, and the Messenger of Allah, peace and blessings of Allah be upon him, offered to compensate him for them. He said: "I am today, O Messenger of Allah, more desirous of Islam."