Sayyiduna Anas (may Allah be pleased with him) narrates: The Prophet (peace and blessings be upon him) led his Companions in prayer. When he completed the prayer, he turned towards the people and said: "Do you recite in prayer behind your imam while the imam is reciting?" The people remained silent. The Prophet (peace and blessings be upon him) said this three times. Then one man, or some people, said: "We do so." The Prophet (peace and blessings be upon him) said: "Do not do so. Let each of you recite Surah al-Fatihah within himself."
Abu Ya'la and al-Tabarani in al-Mu'jam al-Awsat recorded it, and its narrators are "thiqat" (trustworthy).
Hadith Referenceمجمع الزوائد ومنبع الفوائد / كتاب الصلاة / 2642