Silsilat al-Ahadith al-Sahihah

It is narrated from Sayyiduna Abu Hurairah and Sayyidah Aisha (may Allah be pleased with them both) that the Noble Prophet (peace and blessings be upon him) looked into a house and saw that people were praying and reciting aloud. He (peace and blessings be upon him) said to them: "Indeed, the one who is praying is whispering to his Lord, so he should pay attention to Whom he is whispering; therefore, (in prayer) when reciting the Noble Qur'an, you should not raise your voices over one another."