Musnad Abu Ya'la al-Mawsili 140:14

Abu Khaythama narrated to us, 'Umar ibn Yunus narrated to us, 'Ikrimah narrated to us, Yazid al-Raqashi narrated to us, from Anas ibn Malik, who said: I said, "O Abu Hamzah, a people bear witness against us with disbelief and polytheism." Anas said, "Those are the worst of creation and creatures." He said, "And they deny the Hawd (the Cistern)." He said, "I heard the Messenger of Allah, may Allah bless him and grant him peace, say: 'Indeed, I have a Cistern whose width is as that which is between Ayla and the Ka'bah—or he said: San'a. It is whiter than milk and sweeter than honey. In it are vessels [numbering] the count of the stars of the sky. Two spouts from Paradise supply it. Whoever denies it shall not attain its drink.'"