Sahih al-Bukhari 398
Sahih al-Bukhari · Book 8: Prayers (Salat) · The Statement of Allah " And take you (people) the Maqam (place) of Ibrahim (Abraham) (or the stone on which Abrahim stood while he was building the Kabah as a place of prayer (for some of your Salat e.g., two Raka after the Tawaf of Kabah)"
Narrated Ibn `Abbas:
حَدَّثَنَا إِسْحَاقُ بْنُ نَصْرٍ ، قَالَ حَدَّثَنَا عَبْدُ الرَّزَّاقِ ، أَخْبَرَنَا ابْنُ جُرَيْجٍ ، عَنْ عَطَاءٍ ، قَالَ سَمِعْتُ ابْنَ عَبَّاسٍ ، قَالَ لَمَّا دَخَلَ النَّبِيُّ صلى الله عليه وسلم الْبَيْتَ دَعَا فِي نَوَاحِيهِ كُلِّهَا، وَلَمْ يُصَلِّ حَتَّى خَرَجَ مِنْهُ، فَلَمَّا خَرَجَ رَكَعَ رَكْعَتَيْنِ فِي قُبُلِ الْكَعْبَةِ وَقَالَ " هَذِهِ الْقِبْلَةُ " .
When the Prophet (ﷺ) entered the Ka`ba, he invoked Allah in each and every side of it and did not pray till he came out of it, and offered a two-rak`at prayer facing the Ka`ba and said, "This is the Qibla."