The Messenger of Allah ﷺ met Jibreel and said, "Jibreel, I have been sent to an unlettered nation among whom are the elderly woman, the very old man, the young boy, the Jariya, and the man who has never read a book."Jibreel replied, "Muhammad, the Quran has been revealed in seven modes."
حدثنا أحمد بن منيع حدثنا الحسن بن موسى حدثنا شيبان عن عاصم عن زر بن حبيش
لقي رسول الله ﷺ جبريل فقال يا جبريل إني بعثت إلى أمة أميين منهم العجوز والشيخ الكبير والغلام والجارية والرجل الذي لم يقرأ كتابا قط قال يا محمد إن القرآن أنزل على سبعة أحرف
Its isnad is hasan. Ahmad reported it: 5/132, from the hadith of Asim bin Abu Najud, with the same wording, and Ibn Hibban graded it sahih (al-Ihsan): 736.There are also narrations on this topic from Umar [already mentioned: 2943], Huzaifa bin Yaman [Ahmad: 5/132, 385, 391, 400, 405], Abu Hurairah [Ahmad: 2/300, 332], Umm Ayub [5 Ahmad: 6/433, and Humaydi, no. 341], Samura [Ahmad: 5/16], Ibn Abbas [Bukhari, no. 4991, and Muslim, no. 819], Abu Juhaym bin Harith bin Sima [Ahmad: 4/169], Amr bin As [Ahmad: 4/204], and Abu Bakra [Ahmad: 5/41, 51].