Musnad Ahmad 3:133

Abdullah narrated to us, Abu Yahya al-Bazzaz Muhammad ibn Abd al-Rahim narrated to me, al-Hasan ibn Bishr ibn Salm al-Kufi narrated to us, al-Abbas ibn al-Fadl al-Ansari narrated to us, from Hisham ibn Ziyad al-Qurashi, from his father, from Mihjan, the freed slave of Uthman, from Uthman, who said: I heard the Messenger of Allah, peace and blessings of Allah be upon him, saying: "Allah will shade a servant in His shade on a day when there is no shade except His shade: [by him] granting respite to one in difficulty, or remitting [a debt] for a debtor."