It is narrated from Sayyiduna Ubadah bin Samit (may Allah be pleased with him) that the Prophet (peace and blessings of Allah be upon him) led us in a prayer in which he recited aloud. Then he turned towards us and said: "Beware! I see that you recite behind your Imam?" We said: Yes, O Prophet of Allah (peace and blessings of Allah be upon him). So he (peace and blessings of Allah be upon him) said: "I am saying, what is the reason that I am contending with the Qur'an? So when the Imam recites aloud, do not do so, only recite Surah Al-Fatihah, because whoever does not recite Surah Al-Fatihah, his prayer is not valid."