It is narrated from Hazrat Abu Huraira (may Allah be pleased with him) that the Holy Prophet (peace and blessings of Allah be upon him) said: Whoever does not recite Surah Al-Fatiha in the prayer, his prayer is incomplete, incomplete. I asked him, "O Abu Huraira! What if sometimes I am behind the Imam?" He pinched my arm and said, "O Persian! Recite it in your heart."