Musnad Abu Ya'la al-Mawsili 161:65

Ishaq ibn Abi Isra'il narrated to us, Abd al-Razzaq narrated to us, from Yahya ibn al-'Ala', from his maternal uncle Shu'ayb ibn Khalid, from Simak ibn Harb, from Abd Allah ibn Umayrah, from al-Abbas ibn Abd al-Muttalib, who said: We were sitting with the Messenger of Allah (may Allah bless him and grant him peace) at al-Batha', and the Messenger of Allah (may Allah bless him and grant him peace) said: "Do you know what this is?" We said: "The clouds." He said: "And the *muzun* (rain clouds)?" We said: "And the *muzun*." He said: "And the *'inan* (clouds/mist)?" Then we remained silent. He said: "Do you know how much is between the heaven and the earth?" We said: "Allah and His Messenger know best." He said: "Between them is a journey of five hundred years, and between every heaven and the next heaven is a journey of five hundred years, and the thickness of every heaven is a journey of five hundred years. And the seventh heaven, between its bottom and its top, is like what is between the heaven and the earth. Then above that are eight mountain goats (*aw'al*), between their knees and their hooves is like what is between the heaven and the earth. Then above that is the Throne, and nothing of the deeds of the children of Adam is hidden from Him."