It is narrated from Sayyiduna Ibn Umar (may Allah be pleased with him) that the Noble Prophet (peace and blessings be upon him) was observing i'tikaf and delivered a sermon to the people, in which he also said: Beware! Indeed, when any one of you stands in prayer, he is whispering to his Lord, so he should understand the words of the whispering that he is making to his Lord, and (also remember that) no one should raise his voice in recitation over others during prayer.