The Prophet ﷺ entered the Kaʿba along with Usama bin Zaid, ʿUthman bin Talha and Bilal and remained there for a long time. When they came out, I was the first man to enter the Kaʿba. I asked Bilal "Where did the Prophet ﷺ pray?" Bilal replied, "Between the two front Pillars."
دَخَلَ النَّبِيُّ ﷺ 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