Sunan An-Nasa'i

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