Ibn Taymiyyah said regarding the Verse:
إِذۡ نَادَىٰ رَبَّهُۥ نِدَاۤءً خَفِیࣰّا
“When he called out his Lord (Allah) a call in secret.”
“Supplicating in a lower voice is greater in [terms of]
etiquette, because voices are not raised in the presence of kings.”
Al-Fatāwā 16/15