Sahih Muslim
The Book Pertaining to the Excellent Qualities of the Holy Prophet (may Peace be upon them) and His Companions (Kitab Al-Fadail)
Book Number: 030 / Hadith Number: 5705
Anas b. Malik reported Allah's Messenger (may peace be upon him) as saying: My Cistern would be as extensive as the distance between Aila and San'a, of Yemen, and there would be in it jugs like stars in the sky.