O you who believe, do not raise your voices above the voice of the prophet,* nor shall you shout at him as you shout at each other, lest your works become nullified while you do not perceive.
يٰأَيُّهَا الَّذينَ ءامَنوا لا تَرفَعوا أَصوٰتَكُم فَوقَ صَوتِ النَّبِىِّ وَلا تَجهَروا لَهُ بِالقَولِ كَجَهرِ بَعضِكُم لِبَعضٍ أَن تَحبَطَ أَعمٰلُكُم وَأَنتُم لا تَشعُرونَ
yaa ayyuhal lazeena aamanoo laa tarfa’ooo aswaatakum fawqa sawtin Nabiyi wa laa tajharoo lahoo bilqawli kajahri ba’dikum liba ‘din an tahbata a ‘maalukum wa antum laa tash’uroon
*49:2 Whenever the word “prophet” (Nabi) is used in reference to Muhammad, it invariably refers to him during his life, not after his death. Obviously, we cannot possibly raise our voices above Muhammad’s voice, now that he is dead. See also 33:56.