Sunan at-Tirmidhi (Jami-al-Tirmidhi), Chapter: Salah (Prayers)

that when the Prophet (SAW) came to Madinah, he continued to face the direction of Bayt al Maqdis in prayer for sixteen or seventeen months. He longed to turn to the kaabah. So, Allah, the Exalted, revealed (the verse): So, he turned his face towards the Kaabah, and he loved that. A man prayed with him the asr prayer and then passed by a section of the Ansar people while they were in ruku of the salah of asr facing Bayt al-Maqdis. So, he said, "He bears testimony that he prayed with Allah's Messenger (SAW) and indeed he had faced the Kaabah," The narrator said, "They turned their direction while still in ruku."