Yahya bin Abu Kathir narrates: I asked Abu Salamah: Which part of the Qur'an was revealed first? He replied: «یاایھا المدثر» “” I said: (Was this revealed first) or Iqra (was revealed first)? So Abu Salamah said: I asked Sayyiduna Jabir bin Abdullah (may Allah be pleased with him) about this: so he said: («یا ایھا المدثر») was revealed first. So I said: (Was this revealed first) or Iqra (was revealed first)? He said: I will tell you what the Prophet (peace and blessings of Allah be upon him) told us. He said: “I stayed in seclusion in the cave of Hira for a month. When I completed my seclusion, I came down from the mountain. When I reached the lower part of the valley, I was called by a voice. I looked in front of me, behind me, to my right and to my left, but I saw no one. Then I was called again. I looked towards the sky, and there he (an angel) was, on a throne in the open space. Because of this, I was overcome with intense fear. I came to Khadijah and, at my request, she covered me with a cloak and then poured water over me. Then Allah Almighty revealed to me this verse: ‘O you who are wrapped in a cloak! Arise and warn, and magnify your Lord, and purify your garments.’”
Hadith Referenceصحیح ابن حبان / كتاب الوحي / 35
Hadith Gradingفضيلة الشيخ الإمام محمد ناصر الدين الألبانيصحيح - وهو مكرر الذي قبله.فضيلة الشيخ العلّامة شُعيب الأرناؤوطإسناده صحيح على شرط البخاري، الأوزاعي: هو عبد الرحمن بن عمرو إمام أهل الشام في عصره.