Sahih Muslim , Book 4, Hadith 48 (In-Book) ⓘ
Abu Huraira reported: A person entered the mosque and said prayer while the Messenger of Allah was sitting in a nook (of the mosque), and the rest of the hadith is the same as mentioned above, but with this addition:" When you get up to pray, perform the ablution completely, and then turn towards the Qibla and recite takbir (Allah o Akbar =Allah is the Most Great)."
حَدَّثَنَا أَبُو بَكْرِ بْنُ أَبِي شَيْبَةَ، حَدَّثَنَا أَبُو أُسَامَةَ، وَعَبْدُ اللَّهِ بْنُ نُمَيْرٍ، ح وَحَدَّثَنَا ابْنُ نُمَيْرٍ، حَدَّثَنَا أَبِي قَالاَ، حَدَّثَنَا عُبَيْدُ اللَّهِ، عَنْ سَعِيدِ بْنِ أَبِي سَعِيدٍ، عَنْ أَبِي هُرَيْرَةَ، أَنَّ رَجُلاً، دَخَلَ الْمَسْجِدَ فَصَلَّى وَرَسُولُ اللَّهِ صلى الله عليه وسلم فِي نَاحِيَةٍ وَسَاقَا الْحَدِيثَ بِمِثْلِ هَذِهِ الْقِصَّةِ وَزَادَا فِيهِ " إِذَا قُمْتَ إِلَى الصَّلاَةِ فَأَسْبِغِ الْوُضُوءَ ثُمَّ اسْتَقْبِلِ الْقِبْلَةَ فَكَبِّرْ " .
also referenced under: Hadith 397 (Reference) & Book 4, Hadith 782 (USC-MSA)