Quran 49, Al-Hujurat (The Private Chambers) ⓘ

49:3Lo! they who subdue their voices in the presence of the messenger of Allah, those are they whose hearts Allah hath proven unto righteousness. Theirs will be forgiveness and immense reward.

إِنَّ الَّذِينَ يَغُضُّونَ أَصْوَاتَهُمْ عِنْدَ رَسُولِ اللَّهِ أُولَئِكَ الَّذِينَ امْتَحَنَ اللَّهُ قُلُوبَهُمْ لِلتَّقْوَى لَهُمْ مَغْفِرَةٌ وَأَجْرٌ عَظِيمٌ