Surah Luqman, ayah 19

31:19

وَٱقۡصِدۡ فِي مَشۡيِكَ وَٱغۡضُضۡ مِن صَوۡتِكَۚ إِنَّ أَنكَرَ ٱلۡأَصۡوَٰتِ لَصَوۡتُ ٱلۡحَمِيرِ ١٩

Waqsid fī mashyika waghdud min sawtika inna ankaral-aswāti lasawtul-hamīr

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