Messenger of Allah ﷺ came to Mecca through its higher region on the day of the Conquest (of Mecca) riding his she-camel on which Usama was riding behind him. Bilal and ʿUthman bin Talha, one of the servants of the Kaʿba, were also accompanying him till he made his camel kneel in the mosque and ordered the latter to bring the key of the Kaʿba. He opened the door of the Kaʿba and Messenger of Allah ﷺ entered in the company of Usama, Bilal and ʿUthman, and stayed in it for a long period. When he came out, the people rushed to it, and ʿAbdullah bin ʿUmar was the first to enter it and found Bilal standing behind the door. He asked Bilal, "Where did the Prophet ﷺ offer his prayer?" He pointed to the place where he had offered his prayer. ʿAbdullah said, "I forgot to ask him how many rakʿat he had performed." (Using translation from Bukhārī 2988)
أَنَّ رَسُولَ اللهِ ﷺ أَقْبَلَ يَوْمَ الْفَتْحِ مِنْ أَعْلَى مَكَّةَ عَلَى رَاحِلَتِهِ فَرَدَفَ أُسَامَةَ بْنَ زَيْدٍ وَمَعَهُ بِلَالٌ وَمَعَهُ عُثْمَانُ بْنُ طَلْحَةَ مِنَ الْحَجَبَةِ حَتَّى أَنَاخَ فِي الْمَسْجِدِ فَأَمَرَهُ أَنْ يَأْتِيَ بِمِفْتَاحِ الْبَيْتِ فَفَتَحَ وَدَخَلَ رَسُولُ اللهِ ﷺ وَمَعَهُ أُسَامَةُ وَبِلَالٌ وَعُثْمَانُ فَمَكَثَ فِيهَا نَهَارًا طَوِيلًا ثُمَّ خَرَجَ فَاسْتَبَقَ النَّاسُ فَكَانَ عَبْدُ اللهِ بْنُ عُمَرَ أَوَّلَ مَنْ دَخَلَ فَوَجَدَ بِلَالًا وَرَاءَ الْبَابِ قَائِمًا فَسَأَلَهُ أَيْنَ صَلَّى رَسُولُ اللهِ ﷺ؟ فَأَشَارَ لَهُ إِلَى الْمَكَانِ الَّذِي صَلَّى فِيهِ قَالَ عَبْدُ اللهِ فَنَسِيتُ أَنْ أَسْأَلَهُ كَمْ صَلَّى مِنْ سَجْدَةٍ؟