The word(s) "quietly" appears 2 time(s) in 2 verse(s) in Quran in Saheeh International translation.

(1) Say, "Call upon Allah or call upon the Most Merciful. Whichever [name] you call - to Him belong the best names." And do not recite [too] loudly in your prayer or [too] quietly but seek between that an [intermediate] way.

(2) And [mention, O Muhammad], when We directed to you a few of the jinn, listening to the Qur'an. And when they attended it, they said, "Listen quietly." And when it was concluded, they went back to their people as warners.