Musnad Ahmad 32:1961

Muhammad ibn Ja‘far narrated to us, Shu‘bah narrated to us, and Hajjaj narrated to us, he said: Shu‘bah narrated to me, he said: I heard Qatadah narrating from Anas ibn Malik, he said: There was a panic in Medina, so the Messenger of Allah (may Allah bless him and grant him peace) borrowed a horse of ours that was called Mandub. The Messenger of Allah (may Allah bless him and grant him peace) said: "We did not see any panic, and we found it to be a sea."