Musnad Ahmad 27:40

Isma'il narrated to us, Ayyub informed us, from Nafi', from Ibn Umar, who said: "The Messenger of Allah, peace and blessings of Allah be upon him, held a horse race. He sent those that were trained (for racing) from Al-Hafya' — or Al-Hayfa' — to Thaniyat al-Wada'. And he sent those that were not trained from Thaniyat al-Wada' to the Mosque of Banu Zurayq." Abdullah said: "I was a rider that day, and I outpaced the people, and my horse leaped with me into the Mosque of Banu Zurayq."