The Messenger of Allah ﷺ met Jibreel at the Stones of Mira and said, "Jibreel, I have been sent to an unlettered nation, among them the old woman, the elderly man, the young boy, the young Jariya, and the man who has never read a book."Jibreel replied, "Muhammad, the Quran has been revealed in seven modes."
لقي رسول الله ﷺ جبريل عند أحجار المراء 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.
Tirmidhi (2943) and Ahmad (21204) both narrated it from the hadith of Asim, from Zirr bin Hubaysh, from Ubayy bin Kaab, who related the hadith. Its chain is hasan because of Asim, who is Ibn Abu Najud, for he is hasan al-hadith. Ibn Hibban also narrated it through his route in his Sahih (739), as did Diya in al-Mukhtarah (3/373).Tirmidhi said, "Hasan sahih, and it has been narrated from Ubayy bin Kaab through more than one route."I say, it is as he said, for I have gathered several routes from Ubayy bin Kaab.His saying, "at the Stones of Contention," refers to a place in Makkah where Quraysh used to argue with one another.