صحيح مسلم

Abu Harb b. Abu al-Aswad reported on the authority of his father that Abu Musa al-Ash'ari sent for the reciters of Basra. They came to him and they were three hundred in number. They recited the Qur'an and he said: You are the best among the inhabitants of Basra, for you are the reciters among them. So continue to recite it. (But bear in mind) that your reciting for a long time may not harden your hearts as were hardened the hearts of those before you. We used to recite a surah which resembled in length and severity to (Surah) Bara'at. I have, however, forgotten it with the exception of this which I remember out of it:" If there were two valleys full of riches, for the son of Adam, he would long for a third valley, and nothing would fill the stomach of the son of Adam but dust." And we used so recite a surah which resembled one of the surahs of Musabbihat, and I have forgotten it, but remember (this much) out of it:" Oh people who believe, why do you say that which you do not practise" (lxi 2.) and" that is recorded in your necks as a witness (against you) and you would be asked about it on the Day of Resurrection" (xvii. 13).