Musnad Ahmad 30:3344

Yunus ibn Muhammad narrated to us, Muhammad ibn Hilal narrated to us, he said: My father narrated to us, from Abu Hurairah, from the Messenger of Allah, may Allah bless him and grant him peace, who said: "A prayer in my mosque is better than a thousand prayers in what is other than it, except for the Sacred Mosque (al-Masjid al-Haram)."