Surah Al-Isra, ayah 110

17:110

قُلِ ٱدۡعُواْ ٱللَّهَ أَوِ ٱدۡعُواْ ٱلرَّحۡمَٰنَۖ أَيّٗا مَّا تَدۡعُواْ فَلَهُ ٱلۡأَسۡمَآءُ ٱلۡحُسۡنَىٰۚ وَلَا تَجۡهَرۡ بِصَلَاتِكَ وَلَا تُخَافِتۡ بِهَا وَٱبۡتَغِ بَيۡنَ ذَٰلِكَ سَبِيلٗا ١١٠

Qulid'ullāha awid'ur-rahmāna ayyam mā tad'ū falahul-asmā'ul-husnā walā tajhar bisalātika walā tukhāfit bihā wabtaghi bayna dhālika sabīlā

Say, "Call upon Allāh or call upon the Most Merciful [ar-Raḥmān]. 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.