Chapter 9: The Book of the Qiblah
Narrated Al Bara bin Azib: Al Bara bin Azib said: The messenger of Allah (peace be upon him) came to Al-Madinah and prayed toward Bait-al-Maqdis for sixteen months, then he was commanded to pray toward the Ka' bah. A man who had prayed with the prophet (peace be upon him) passed by some of the Ansar and said: "I bear witness that the messenger of Allah (peace be upon him) has been commanded to face toward the Ka' bah. So they turned to face the Ka' bah".
Sunan an-Nasa'i 742