Muwatta Malik, Book 14, Hadith 464 (In-Book)

Yahya related to me from Malik from Yahya ibn Said that Said ibn al-Musayyab said, "The Messenger of Allah, may Allah bless him and grant him peace, prayed towards the Baytal-Maqdis for sixteen months after arriving in Madina. Then the qibla was moved, two months before the battle of Badr. "

وَحَدَّثَنِي عَنْ مَالِكٍ، عَنْ يَحْيَى بْنِ سَعِيدٍ، عَنْ سَعِيدِ بْنِ الْمُسَيَّبِ، أَنَّهُ قَالَ صَلَّى رَسُولُ اللَّهِ صلى الله عليه وسلم بَعْدَ أَنْ قَدِمَ الْمَدِينَةَ سِتَّةَ عَشَرَ شَهْرًا نَحْوَ بَيْتِ الْمَقْدِسِ ثُمَّ حُوِّلَتِ الْقِبْلَةُ قَبْلَ بَدْرٍ بِشَهْرَيْنِ ‏.‏

sunnah.com

also referenced under: Book 14, Hadith 7 (USC-MSA)