Musnad Abu Ya'la al-Mawsili 115:128

Abu Khaythama narrated to us, Yahya narrated to us, from Shu'bah, Qatadah narrated to us, from Anas, who said: There was a state of alarm in Medina, so the Messenger of Allah (peace and blessings of Allah be upon him) rode a horse belonging to Abu Talha. He then said: "We did not see anything, and we found it to be a sea."