Abu al-Fayd narrates: I heard Abu Shaybah al-Mahri saying that a man asked Mu'adh bin Jabal (may Allah be pleased with him) about recitation behind the imam, and he said: When the imam recites aloud, recite Surah al-Fatihah and 'Say: He is Allah, the One' [Surah al-Ikhlas: 1], and when it is a silent prayer, then too recite Surah al-Fatihah within yourself, and do not disturb those on your right and left. Among them is Abdullah bin Abbas (may Allah be pleased with them both).
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصلاة / 2938