Language:
كتاب الصلاة
8  
Prayers (Salat)
(30)
Chapter: 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)"
(30)
بَابُ قَوْلِ اللَّهِ تَعَالَى: {وَاتَّخِذُوا مِنْ مَقَامِ إِبْرَاهِيمَ مُصَلًّى}
Sahih al-Bukhari 398

Narrated Ibn `Abbas:

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."

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 ‏"‏‏.‏
Reference : Sahih al-Bukhari 398
In-book reference : Book 8, Hadith 49
USC-MSA web (English) reference : Vol. 1, Book 8, Hadith 391
  (deprecated numbering scheme)