Sahih Bukhari

Narrated Abu Sa`id Al-Mualla:While I was praying, the Prophet (ﷺ) passed by and called me, but I did not go to him till I had finished my prayer. When I went to him, he said, ""What prevented you from coming?"" I said, ""I was praying."" He said, ""Didn't Allah say"" ""O you who believes Give your response to Allah (by obeying Him) and to His Apostle."" (8.24) Then he added, ""Shall I tell you the most superior Sura in the Qur'an before I go out of the mosque?"" When the Prophet (ﷺ) intended to go out (of the Mosque), I reminded him and he said, ""That is: ""Al hamdu-li l-lahi Rabbil-`alamin (Surat-al-fatiha)' which is the seven oft repeated verses (Al-Mathani) and the Grand Qur'an which has been given to me