Musnad Ahmad 31:925

'Affan narrated to us, Hammad bin Salamah narrated to us, 'Ali bin Zayd informed us, from Abu Nadrah, from Abu Sa'id al-Khudri, that 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 sea, around it are snakes." The Messenger of Allah (peace and blessings of Allah be upon him) said: "That is the throne of Iblis."