Muwatta Imam Malik (Riwayat Ibn al-Qasim)

And with the same chain of narration (from Sayyiduna Abdullah bin Umar, may Allah be pleased with him), it is narrated that the Messenger of Allah, peace and blessings be upon him, raced those horses which had been made lean and prepared for jihad from Hafyaa (a place) to Thaniyyat al-Wada' (another place), and those which had not been prepared were raced from Thaniyya to the mosque of Banu Zuraiq. And Abdullah bin Umar, may Allah be pleased with them both, was among those who participated in this competition.