Sahih Muslim
The Book of Pilgrimage (Kitab Al-Hajj)
Book Number: 007 / Hadith Number: 3220
Abu Haraira (Allah be pleased with him) reported Allah's Messenger (way peace be upon him) as saying: One should undertake journey to three mosques: the mosque of the Ka'ba, my mosque, and the mosque of Elia (Bait al-Maqdis).