Musnad Abu Ya'la al-Mawsili 155:164

Amr al-Naqid narrated to us, Abdullah bin Salim al-Raqqi narrated to us, Rishdin bin Sa’d narrated to us, from Uqayl bin Khalid, from al-Zuhri, from Abu Salamah, from Abu Hurayrah, who said: The Messenger of Allah (peace and blessings of Allah be upon him) said: "Indeed, for everything there is refuse, and the refuse of the mosque is—no, by Allah, and yes, by Allah."