Surah Taha 20:7

وَإِن تَجْهَرْ بِٱلْقَوْلِ فَإِنَّهُۥ يَعْلَمُ ٱلسِّرَّ وَأَخْفَى

And if you speak aloud - then indeed, He knows the secret and what is [even] more hidden.

Translation: Saheeh International

Tafsir

And should you be loud in your speech in remembrance of God or supplication then God has no need for this to be spoken loud then indeed He knows the secret and that which is yet more hidden than that secret namely that which the soul whispers to itself and that which occurs to the mind but which you do not speak of to …

Excerpt from Tafsir al-Jalalayn, commentary on 20:7, via Quran.com. The reader has the full commentary and 9 more tafsirs.