The importance of suratul fatihah

[Muslim:4:775] Abu Huraira reported: The Apostle of Allah (may peace be upon him) said: If anyone observes prayer in which he does not recite Umm al-Qur'an(Surah Fatiha), It is deficient [he said this three times] and not complete. It was said to Abu Huraira: At times we are behind the Imam. He said: Recite it inwardly.