وَاقْصِدْ فِي مَشْيِكَ وَاغْضُضْ مِن صَوْتِكَ إِنَّ أَنكَرَ الْأَصْوَاتِ لَصَوْتُ الْحَمِيرِ
[31:19]
And pursue the right course in your going about and lower your voice; surely the most hateful of voices is braying of the asses.
"And be moderate in thy pace, and lower thy voice; for the harshest of sounds without doubt is the braying of the ass."
Be modest in thy bearing and subdue thy voice. Lo! the harshest of all voices is the voice of the ass.