قُلِ ادعُوا اللَّهَ أَوِ ادعُوا الرَّحمـٰنَ ۖ أَيًّا ما تَدعوا فَلَهُ الأَسماءُ الحُسنىٰ ۚ وَلا تَجهَر بِصَلاتِكَ وَلا تُخافِت بِها وَابتَغِ بَينَ ذٰلِكَ سَبيلًا

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.