It is narrated from Hazrat Abu Saeed bin Mualla (may Allah be pleased with him) that once I was offering prayer, and by chance, the Prophet (peace and blessings of Allah be upon him) passed by. The Prophet (peace be upon him) called me, but I did not come until I had completed my prayer. After that, I went to him, and the Prophet (peace be upon him) said, "What kept you from coming to me?" I replied, "I was offering prayer." The Prophet (peace be upon him) said, "Did Allah not say: O you who believe! Respond to Allah and to the Messenger when he calls you to that which gives you life?" Then he said, "Shall I not teach you the greatest Surah of the Qur'an before you leave the mosque?" When the Prophet (peace be upon him) was about to leave the mosque, I reminded him. The Prophet (peace be upon him) said, "It is Surah Al-Fatiha. It is the seven oft-repeated verses and the Great Qur'an which has been given to me."