Book 20: Shortening the Prayers (At-Taqseer)
Volume 2, Book 20, Number 186: Narrated Ibn Abbas : The Prophet once stayed for nineteen days and prayed shortened prayers. So when we travel led (and stayed) for nineteen days, we used to shorten the prayer but if we travelled (and stayed) for a longer period we used to offer the full prayer. Volume 2, Book 20, 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." Volume 2, Book 20, Number 188: Narrated 'Abdullah bin 'Umar: I offered the prayer with the Prophet, Abu Bakr and 'Umar at Mina and it was of two Rakat. 'Uthman in the early days of his caliphate did the same, but later on he started praying the full prayer. Volume 2, Book 20, Number 189: Narrated Haritha bin Wahab: The Prophet I led us