[Machine] While people were performing the Fajr prayer in Quba, a man came to them and said, "Verily, the Messenger of Allah ﷺ has been revealed the Quran and he has been commanded to face the Kaaba in prayer, so face towards it." The people's faces were initially directed towards Sham (Syria) but they turned and faced towards the Kaaba.  

بَيْنَمَا النَّاسُ فِي صَلَاةِ الْفَجْرِ فِي قُبَاءٍ إذ جَاءَهُمْ رَجُلٌ فَقَالَ «إِنَّ رَسُولَ اللَّهِ ﷺ أُنْزِلَ عَلَيْهِ الْقُرْآنُ وَأُمِرَ أَنْ يَسْتَقْبِلَ الْكَعْبَةَ فَاسْتَقْبِلُوهَا وَكَانَ وُجهُ النَّاسِ إِلَى الشَّامِ فَاسْتَدَارُوا فَوَجَّهُوا إِلَى الْكَعْبَةِ»  

when the Prophet (May peace be upon him) turned towards the Ka’bah (in prayer), the people asked : Messenger of Allah (May peace be upon him)! what will happen with those who died while they prayed with their faces towards Jerusalem ? Allah the Exalted, then revealed : “And never would Allah make your faith of no effect.” (Using translation from Abū Dāʾūd 4680)   

قِيلَ يَا رَسُولَ اللَّهِ أَرَأَيْتَ الَّذِينَ مَاتُوا وَهُمْ يُصَلُّونَ إِلَى بَيْتِ الْمَقْدِسِ؟ فَأَنْزَلَ اللَّهُ تَعَالَى {وَمَا كَانَ اللَّهُ لِيُضِيعَ إِيمَانَكُمْ} [البقرة 143]