The Book of Prayers (Kitab Al-Salat)
Muslim :: Book 4 : Hadith 1473
Anas b. Malik reported: We went out from Medina to Mecca with the Messenger of Allah (may peace be upon him) and he prayed two rak'ahs at each time of prayer till we returned to Medina. I said: For how long did he stay in Mecca? He said: (For) ten (days).