Abu Saeed bin al-Mu'alla said that when he was praying the Prophet صلی اللہ علیہ وسلم passed by him and he called him. He said: I prayed ant then I came to him. He asked: What prevented you from answering me ? He replied: I was praying. He said: Has not Allah said: O you who believe, respond to Allah and the Messenger when he calls you to that which gives you life ? (8: 24) Let me teach you the greatest surah from the Quran or in the Quran (the narrator Khalid doubted) before I leave the mosque. I said: (I shall memorize) your saying. He said: It is: Praise be to Allah, the Lord of the Universe which is the seven oft-repeated verses, and the mighty Quran.