Musnad Ahmad 21:8

'Abd al-Razzaq narrated to us, Yahya ibn al-'Ala' informed us, from his paternal uncle Shu'ayb ibn Khalid, Simak ibn Harb narrated to me, from 'Abd Allah ibn 'Umayrah, from al-'Abbas ibn 'Abd al-Muttalib, who said: We were sitting with the Messenger of Allah, peace and blessings of Allah be upon him, at al-Batha', and a cloud passed by. The Messenger of Allah, peace and blessings of Allah be upon him, said: "Do you know what this is?" We said: The cloud (al-sahab). He said: "And the rain-cloud (al-muzn)." We said: And the rain-cloud. He said: "And the clouds (al-'inan)." He said: So we remained silent. Then 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 from every heaven to a heaven is a journey of five hundred years, and the thickness of every heaven is a journey of five hundred years. Above the seventh heaven is a sea, between its bottom and its top is as between the heaven and the earth. Then above that are eight mountain goats (wa'l), between their knees and their hooves is as between the heaven and the earth. Then above that is the Throne, between its bottom and its top is as between the heaven and the earth. And Allah, Blessed and Exalted is He, is above that, and nothing of the deeds of the children of Adam is hidden from Him."