Sahih Bukhari Volume 4, Book 52, Hadith Number 122.

Narated By Abu Ishaq from Musa bin ‘Uqba from Mafia from Ibn ‘Umar : Who said: “Allah’s Apostle arranged a horse race amongst the horses that had been made lean, letting them start from Al-Hafya’ and their limit (distance of running) was up to Thaniyat-al-Wada’. I asked Musa, ‘What was the distance between the two places?’ Musa replied, ‘Six or seven miles. He arranged a race of the horses which had not been made lean sending them from Thaniyat-al-Wada’, and their limit was up to the mosque of Bani Zuraiq.’ I asked, ‘What was the distance between those two places?’ He replied ‘One mile or so.’ Ibn ‘Umar was amongst those who participated in that horse race.”