Abu Hurairah (may Allah be pleased with him) narrates that the Messenger of Allah (peace be upon him) said: "Any prayer in which Surah Al-Fatihah is not recited is not sufficient." (Abdur Rahman) says: I asked, "If I am praying behind the Imam?" So he (the Prophet) took my hand and said, "O Persian, (at that time) recite it in your heart."