Sayyiduna Umar bin Khattab (may Allah be pleased with him) narrated that I heard Hisham bin Hakim bin Hizam reciting Surah Al-Furqan in a way different from the recitation which I recite, although this recitation was taught to me by the Messenger of Allah (peace and blessings be upon him). I was about to seize him, but I gave him respite until he finished (the prayer). After that, I wrapped his cloak around his neck and seized him, and brought him to the Messenger of Allah (peace and blessings be upon him). I said to him, "I heard him reciting in a manner different from what you taught me." The Prophet (peace and blessings be upon him) said to me, "Let him go first." Then he said to him, "Recite." He recited in the same way as before. The Prophet (peace and blessings be upon him) said, "It was revealed in this way." Then he said to me, "Now you recite." So I recited, and he said, "It was revealed in this way also." The Qur'an has been revealed in seven modes of recitation, so recite in whichever is easy for you.

Sayyiduna Ibn Abbas (may Allah be pleased with them both) narrated that the Messenger of Allah (peace and blessings be upon him) said: Jibreel taught me the Qur'an according to one dialect of the Arabs, but I continued to seek an increase in it until it was revealed in seven dialects of the Arabs.