Word by Word Analysis

إِنَّ ٱلَّذِينَ يَغُضُّونَ أَصْوَٰتَهُمْ عِندَ رَسُولِ ٱللَّهِ أُو۟لَـٰٓئِكَ ٱلَّذِينَ ٱمْتَحَنَ ٱللَّهُ قُلُوبَهُمْ لِلتَّقْوَىٰ ۚ لَهُم مَّغْفِرَةٌ وَأَجْرٌ عَظِيمٌ 3

Indeed, those who lower their voices before the Messenger of Allāh - they are the ones whose hearts Allāh has tested for righteousness. For them is forgiveness and great reward.