Musnad Ahmad 30:1676

Khalaf narrated to us, Ibn Abi Dhi’b narrated to us, from Abu al-Walid, from Abu Hurairah, from the Prophet (peace and blessings of Allah be upon him), who said: "I would not love to have gold equal to Uhud with me, such that three nights pass by while I still have a dinar of it, except for something I have set aside for my creditor."