Musnad Abu Ya'la al-Mawsili 160:159

Muhammad ibn Bakkar narrated to us, Abu Ma'shar narrated to us, from Sa'id, from Abu Hurayrah, who said: The Messenger of Allah (may Allah bless him and grant him peace) said: "A prayer in this mosque of mine is better than a thousand prayers in what is other than it, except for the Sacred Mosque (al-Masjid al-Haram)."