Sunan Abi Dawud Book 15, Hadith 99

‘Abd Allah bin Umar said “The Apostle of Allaah(ﷺ) held race between the horses which had been made lean by training from Al Hafya’. The goal was Thaniyyat Al Wada’ and he held a race between the horses Banu Zuraiq and ‘Abd Allaah was one of the racers.