Sahih al-Bukhari 4493
Narrated Ibn `Umar:
While some people were at Quba (offering) morning prayer, a man came to them and said, "Last night 
Qur'anic Verses have been revealed whereby the Prophet (ﷺ) has been ordered to face the Ka`ba (at 
Mecca), so you too should face it." So they, keeping their postures, turned towards the Ka`ba. 
Formerly the people were facing Sham (Jerusalem) (Allah said):-- 
"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), and whence-so-ever you are, turn your face towards it 
(when you pray)" (2.150)
حَدَّثَنَا مُوسَى بْنُ إِسْمَاعِيلَ، حَدَّثَنَا عَبْدُ الْعَزِيزِ بْنُ مُسْلِمٍ، حَدَّثَنَا عَبْدُ اللَّهِ بْنُ دِينَارٍ، قَالَ سَمِعْتُ ابْنَ عُمَرَ ـ رضى الله عنهما ـ يَقُولُ بَيْنَا النَّاسُ فِي الصُّبْحِ بِقُبَاءٍ إِذْ جَاءَهُمْ رَجُلٌ فَقَالَ أُنْزِلَ اللَّيْلَةَ قُرْآنٌ، فَأُمِرَ أَنْ يَسْتَقْبِلَ الْكَعْبَةَ، فَاسْتَقْبِلُوهَا‏.‏ وَاسْتَدَارُوا كَهَيْئَتِهِمْ، فَتَوَجَّهُوا إِلَى الْكَعْبَةِ وَكَانَ وَجْهُ النَّاسِ إِلَى الشَّأْمِ‏.‏