Sahih Muslim
The Book of Pilgrimage (Kitab Al-Hajj)
Book Number: 007 / Hadith Number: 3213
Ibn 'Umar (Allah be pleased with them) reported Allah's Apostle (may peace be upon him) as saying: Prayer in this mosque of mine is better than a thousand prayers (observed in other mosque.) besides it, except that of Masjid al-Haram.