﴿ وَٱقْصِدْ فِى مَشْيِكَ وَٱغْضُضْ مِن صَوْتِكَ ۚ إِنَّ أَنكَرَ ٱلْأَصْوَٰتِ لَصَوْتُ ٱلْحَمِيرِ ﴾

““Hence, be modest in thy bearing, and lower thy voice: for, behold, the ugliest of all voices is the [loud] voice of asses…””

(Be modest in thy bearing and subdue your voice) lower your voice and do not be sharp-tongued. (Lo! The harshest of all voices) He says: the most odious and evil of all voices (is the voice of the ass.