Musnad Ahmad 34:3

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: "Then 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."