Ubada bin As-Samit · The Book on Salat (Prayer)

the Prophet said: "There is no Salat for the one who does not recite Fatihatil-Kitab."

"Allah's Messenger prayed the Subh prayer, and he had difficulty with the recitation. When turned (after finishing) he said: 'I think that you are reciting behind your Imam?'" He said: "We said: 'Yes, Messenger of Allah, by Allah!' He said: 'Do not do that, except for Umm Al-Kitab, for there is no Salat for one who does not recite it.'"