Musnad Ahmad 30:3820

Hashim narrated to us, Abu Mu'awiyah narrated to us, from Mansur, from Abu 'Uthman, the freed slave of the family of Al-Mughirah ibn Shu'bah, from Abu Hurayrah, who said: I heard him saying: Muhammad, the Messenger of Allah, Abu al-Qasim, may Allah bless him and grant him peace, the owner of this chamber, said: "Mercy is not snatched away except from a wretched person."