Musnad Abu Ya'la al-Mawsili 115:157

Muhammad ibn al-Muthanna narrated to us, Muhammad ibn Ja'far narrated to us, Shu'bah narrated to us, and I heard Qatadah narrating from Anas: That there was a panic in Medina, so the Messenger of Allah (peace and blessings of Allah be upon him) borrowed a horse that was called Mandub. The Messenger of Allah (peace and blessings of Allah be upon him) said: "We did not see any panic, and we found it to be a sea."