Musannaf Ibn Abi Shaybah

Hazrat Yahya bin Abi Ishaq says that I offered the Maghrib prayer behind Hakam bin Ayyub. Abu Mulaeeh was standing next to Ibn Usama. I heard Abu Mulaeeh reciting Surah Al-Fatiha. When the Imam finished the prayer with salam, I asked Abu Mulaeeh, "Were you reciting (Qur'an) behind the Imam, even though the Imam was also reciting?" He said, "Did you hear anything?" I said, "Yes." He replied, "Yes, I was reciting."