From Sahih Bukhari (Hadith 4492):
Narrated Al-Bara:We prayed along with the Prophet (ﷺ) facing Jerusalem for sixteen or seventeen months. Then Allah ordered him to turn his face towards the Qibla (in Mecca):-- "And from whence-so-ever you start forth (for prayers) turn your face in the direction of (the Sacred Mosque of Mecca) Al-Masjid-ul Haram
Reference: Bukhari 4492