Sahih Bukhari
Shortening the Prayers (At-Taqseer)
Volume: 002 / Book Number: 020 / Hadith Number: 187
Narrated Yahya bin Ishaq:
I heard Anas saying, "We travelled with the Prophet from Medina to Mecca and offered two Rakat (for every prayer) till we returned to Medina." I said, "Did you stay for a while in Mecca?" He replied, "We stayed in Mecca for ten days."