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."
Sahih al-Bukhari Book 8, Hadith 49
← Previous Hadith Someone came to Ibn `Umar and said, "Here is Allah's Messenger (ﷺ) entering the Ka`ba." Ibn `Umar said, "I went there but the Prophet (ﷺ) had come out of the Ka`ba and I found Bilal standing between its two doors. I asked Bilal, 'Did the Prophet (ﷺ) pray in the Ka`ba?' Bilal replied, 'Yes, he prayed two rak`at between the two pillars which are to your left on entering the Ka`ba. Then Allah's Messenger (ﷺ) came out and offered a two-rak`at prayer facing the Ka`ba.' "

Sahih al-Bukhari Book 8, Hadith 48 Next Hadith → Allah's Messenger (ﷺ) prayed facing Baitul-Maqdis for sixteen or seventeen months but he loved to face the Ka`ba (at Mecca) so Allah revealed: "Verily, We have seen the turning of your face to the heaven!" (2:144) So the Prophet (ﷺ) faced the Ka`ba and the fools amongst the people namely "the Jews" said, "What has turned them from their Qibla (Baitul-Maqdis) which they formerly observed"" (Allah revealed): "Say: 'To Allah belongs the East and the West. He guides whom he will to a straight path'." (2:142) A man prayed with the Prophet (facing the Ka`ba) and went out. He saw some of the Ansar praying the `Asr prayer with their faces towards Baitul-Maqdis, he said, "I bear witness that I prayed with Allah's Messenger (ﷺ) facing the Ka`ba." So all the people turned their faces towards the Ka`ba.

Sahih al-Bukhari Book 8, Hadith 50