Sura 31 Luqman, aya 19

1. وَاقْصِدْ فِي مَشْيِكَ وَاغْضُضْ مِنْ صَوْتِكَ ۚ إِنَّ أَنْكَرَ الْأَصْوَاتِ لَصَوْتُ الْحَمِيرِ

   And be moderate in your pace and lower your voice; indeed, the most disagreeable of sounds is the voice of donkeys."

   31:19

Tafsiri: Saheeh International