Sahih Muslim Book 4, Hadith Number 1473.

Chapter : Compensation of the missed prayer and excellence of observing it promptly.

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).