I asked Aba Salama, "Which Sura of the Qur'an was revealed first?" He replied, "O you, wrapped-up' (Al-Muddaththir)." I said, "I have been informed that it was, 'Read, in the Name of your Lord who created (i.e. Surat Al-Alaq)...similar to the narration related by `Ali bin Al-Mubarak, 444 above).
Sahih al-Bukhari Book 65, Hadith 444
← Previous Hadith The Prophet (ﷺ) said, "I was in a seclusion in the cave of Hira........."(similar to the narration related by `Ali bin Al-Mubarak, 444 above).

Sahih al-Bukhari Book 65, Hadith 443 Next Hadith → I heard the Prophet (ﷺ) describing the period of pause of the Divine Inspiration. He said in his talk, "While I was walking, I heard voices from the sky. I looked up, and behold ! I saw the same Angel who came to me in the cave of Hira' sitting on a chair between the sky and the earth. I was too much afraid of him (so I returned to my house) and said, 'Fold me up in garments!' They wrapped me up. Then Allah revealed: 'O you wrapped...and desert the idols before the prayer became compulsory.' Rujz means idols.

Sahih al-Bukhari Book 65, Hadith 445