When the verse was revealed:" Do not raise your voice louder than the voice of the Apostle," no mention was made of Sa'd b, Mu'adh in it.
لَمَّا نَزَلَتْ { لاَ تَرْفَعُوا أَصْوَاتَكُمْ فَوْقَ صَوْتِ النَّبِيِّ} وَلَمْ يَذْكُرْ سَعْدَ بْنَ مُعَاذٍ فِي الْحَدِيثِ