Dalil
العربية

Quran Al-Mulk 67:13

وَأَسِرُّواْ قَوۡلَكُمۡ أَوِ ٱجۡهَرُواْ بِهِۦٓۖ إِنَّهُۥ عَلِيمُۢ بِذَاتِ ٱلصُّدُورِ

Translation

And conceal your speech or publicize it; indeed, He is Knowing of that within the breasts.