Hadith Number 039.
Sahih Bukhari Book 02. Belief
Narated By Al-Bara' (bin 'Azib) :
When the Prophet came to Medina,
he stayed first with his grandfathers
or maternal uncles from Ansar. He
offered his prayers facing Baitul-
Maqdis (Jerusalem) for sixteen or
seventeen months, but he wished that
he could pray facing the Ka'ba (at
Mecca). The first prayer which he
offered facing the Ka'ba was the 'Asr
prayer in the company of some
people. Then one of those who had
offered that prayer with him came
out and passed by some people in a
mosque who were bowing during
their prayers (facing Jerusalem). He
said addressing them, "By Allah, I
testify that I have prayed with Allah's
Apostle facing Mecca (Ka'ba).'
Hearing that, those people changed
their direction towards the Ka'ba
immediately. Jews and the people of
the scriptures used to be pleased to
see the Prophet facing Jerusalem in
prayers but when he changed his
direction towards the Ka'ba, during
the 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 we did
not know what to say about them
(regarding their prayers.) Allah then
revealed: And Allah would never
make your faith (prayers) to be lost
(i.e. the prayers of those Muslims
were valid).'" (2:143).