From Sahih Bukhari (Hadith 403):
Narrated `Abdullah bin `Umar:While the people were offering the Fajr prayer at Quba' (near Medina), someone came to them and said: "It has been revealed to Allah's Messenger (ﷺ) tonight, and he has been ordered to pray facing the Ka`ba." So turn your faces to the Ka`ba. Those people were facing Sham (Jerusalem) so they turned their faces towards Ka`ba (at Mecca)
Reference: Bukhari 403