Sahih Bukhari

When the Prophet (ﷺ) came to Medina, he stayed first with his grandfathersor maternal uncles from Ansar. He offered his prayers facingBaitul-Maqdis (Jerusalem) for sixteen or seventeen months, but hewished that he could pray facing the Ka'ba (at Mecca). The firstprayer which he offered facing the Ka'ba was the 'Asr prayer in thecompany of some people. Then one of those who had offered that prayerwith him came out and passed by some people in a mosque who werebowing during their prayers (facing Jerusalem). He said addressingthem, "By Allah, I testify that I have prayed with Allah's Messenger (ﷺ)facing Mecca (Ka'ba).' Hearing that, those people changed theirdirection towards the Ka'ba immediately. Jews and the people of thescriptures used to be pleased to see the Prophet (ﷺ) facing Jerusalem inprayers but when he changed his direction towards the Ka'ba, duringthe prayers, they disapproved of it.Al-Bara' added, "Before we changed our direction towards the Ka'ba(Mecca) in prayers, some Muslims had died or had been killed and wedid not know what to say about them (regarding their prayers.) Allahthen revealed: And Allah would never make your faith (prayers) to belost (i.e. the prayers of those Muslims were valid).' " (2:143).