Sayyiduna Abu Sa'id Khudri (may Allah be pleased with him) narrates that the Prophet Muhammad (peace and blessings be upon him) performed i'tikaf in the mosque and heard the companions reciting (the Qur'an) in loud voices, while he (peace be upon him) was in his tent-like enclosure. He (peace be upon him) removed the curtain and said: "Be aware, indeed all of you are supplicating to your Lord, so do not cause harm to one another, and do not recite loudly over each other." In the narration of Muhammad bin Yahya, these words are mentioned: "or in prayer (do not recite loudly)."