Musnad Abu Ya'la al-Mawsili 112:6

'Abd al-Rahman ibn Sallam Abu Harb narrated to us, Hammad narrated to us, from 'Ali ibn Zayd, from al-Hasan, from Anas: That the Hawd (the Cistern) was mentioned in the presence of 'Ubayd Allah ibn Ziyad, and it was as if he denied it. This reached Anas, so he said, "Indeed, I will surely distress him." He went to him and said, "What is it that you denied regarding the Hawd?" He said, "Did you hear it, O Abu Hamzah, from the Messenger of Allah (may Allah bless him and grant him peace)?" He said, "Yes, more than such and such a number of times. I heard the Messenger of Allah (may Allah bless him and grant him peace) say: 'The distance between the two ends of my Hawd is as the distance between Ayla and Makkah, or between San'a and Makkah. And its vessels are more numerous than the stars of the sky.'"