Musnad Abu Ya'la al-Mawsili 116:28

Ahmad narrated to us, Shababa narrated to us, Shu'bah narrated to us, from Qatadah, from Anas, who said: There was a panic in Medina, so the Prophet, peace and blessings of Allah be upon him, borrowed a horse from Abu Talha called Mandub. He said: So he rode it. When he returned, 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."