Sahih al-Bukhari 504
Sahih al-Bukhari · Book 8: Prayers (Salat) · To offer non-congregational As-Salat (the prayers) between the pillars
Narrated Ibn `Umar:
حَدَّثَنَا مُوسَى بْنُ إِسْمَاعِيلَ ، قَالَ حَدَّثَنَا جُوَيْرِيَةُ ، عَنْ نَافِعٍ ، عَنِ ابْنِ عُمَرَ ، قَالَ دَخَلَ النَّبِيُّ صلى الله عليه وسلم الْبَيْتَ وَأُسَامَةُ بْنُ زَيْدٍ وَعُثْمَانُ بْنُ طَلْحَةَ وَبِلاَلٌ، فَأَطَالَ ثُمَّ خَرَجَ، وَكُنْتُ أَوَّلَ النَّاسِ دَخَلَ عَلَى أَثَرِهِ فَسَأَلْتُ بِلاَلاً أَيْنَ صَلَّى قَالَ بَيْنَ الْعَمُودَيْنِ الْمُقَدَّمَيْنِ.
The Prophet (ﷺ) entered the Ka`ba along with Usama bin Zaid, `Uthman bin Talha and Bilal and remained there for a long time. When they came out, I was the first man to enter the Ka`ba. I asked Bilal "Where did the Prophet (ﷺ) pray?" Bilal replied, "Between the two front Pillars."