Al-Israa 17:110

Say, “Call upon Allah or call upon the Most Compassionate[87] – whichever name you call, to Him belong the Most Beautiful Names.” Do not be too loud in your prayer, nor too quiet, but seek a way in between[88].

[87] The Makkans heard the Prophet (ﷺ) praying to Allah, once as Allah and on another occasion as Al-Rahmān, and claimed that he was praying to two different gods. [Majmū‘ al-Fatāwā, Ibn Taymiyyah, 14:15] Both are two Names for Allah, the One and Only God.
[88] Abdullāh ibn Abbās (رضي الله عنهما) reported the reason behind the revelation of this verse: “It came down when the Messenger of Allah (ﷺ) was lying low in Makkah. When he used to lead his Companions in Prayer and raise his voice and the pagans heard him, they would curse the Qur’an and He Who sent it down. So Allah said to His Messenger: “Do not raise your voice is Prayer upon which the pagans would hear you, yet not too quiet that your Companions may not hear you. Make them hear the Qur’an but do not raise your voice to that extent; seeking a middle way between them.” [Al-Bukhārī: 4722; Muslim: 446].

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.

110. Say (O Muhammad صلى الله عليه و سلم): "Invoke Allâh or invoke the Most Gracious (Allâh), by whatever name you invoke Him (it is the same), for to Him belong the Best Names. And offer your Salât (prayer) neither aloud nor in a low voice, but follow a way between.

Say (unto mankind): Cry unto Allah, or cry unto the Beneficent, unto whichsoever ye cry (it is the same). His are the most beautiful names. And thou (Muhammad), be not loud-voiced in thy worship nor yet silent therein, but follow a way between.