Musnad Ahmad 30:2815

Husayn narrated to us, he said: Shayban narrated to us, from Mansur, from Abu Uthman, the freed slave of al-Mughirah ibn Shu'bah, who said: I heard Abu Hurayrah, while we were in the Mosque of the Messenger of Allah (may Allah bless him and grant him peace), saying: Muhammad, the Messenger of Allah (may Allah bless him and grant him peace), Abu al-Qasim, the owner of this chamber, said: "Mercy is not removed except from a wretched person."