Translation of the verse 110 from Surah Al-Isra’ : Number of verses 111 - - page 293 - Part 15.
Say (O Muhammad SAW): "Invoke Allah or invoke the Most Beneficent (Allah), by whatever name you invoke Him (it is the same), for to Him belong the Best Names. And offer your Salat (prayer) neither aloud nor in a low voice, but follow a way between.
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.
(17:110) (O Prophet), say to them, "You may call Him by any name, Allah or Rahman, for it is all the same by whichsoever name you call Him because all His names are most excellent. *123 And do not raise your voice high in your Prayer nor make it very low but adopt the middle way *124 between these two
*123) This is the answer to another objection of the disbelievers. They said, "We have heard the name Allah for the Creator but where from have you brought the name Rahman ?" This was because the name "Rehman " was not used for Allah and they did not like it.
*124) This instruction was given at Makkah. Ibn 'Abbas relates that when the Holy Prophet or his Companions offered their Prayers, they recited the Qur'an jn a loud voice. At this the disbelievers would raise a hue and cry and often called them names. Therefore, they wen enjoined that they should neither say their Prayers in such a loud voice as might incite the disbelievers nor should they say it in such a low voice that their own Companions might not hear it. This instruction was discontinued under the changed conditions at Al-Madinah. However, if the Muslims thay have to face the same conditions, at any place or at any time, they should observe the same instruction.