Musnad Ahmad 33:1048

Mu'ammal narrated to us, Hammad narrated to us, Ali—meaning Ibn Zayd—narrated to us, from Abu Nadrah, from Jabir, who said: The Messenger of Allah (peace and blessings of Allah be upon him) said to Ibn Sa'id: "What do you see?" He said: "I see a throne upon the water—or he said: upon the sea—surrounded by snakes." The Messenger of Allah (peace and blessings of Allah be upon him) said: "That is the throne of Iblis."