"The Messenger of Allah ﷺ said: 'When the reciter says Amin, then say: "Amin" too, for the angels say Amin and if a person's Amin coincides with the Amin of the angels, Allah will forgive his previous sins"
قَالَ رَسُولُ اللَّهِ ﷺ إِذَا أَمَّنَ الْقَارِئُ فَأَمِّنُوا فَإِنَّ الْمَلاَئِكَةَ تُؤَمِّنُ فَمَنْ وَافَقَ تَأْمِينُهُ تَأْمِينَ الْمَلاَئِكَةِ غَفَرَ اللَّهُ لَهُ مَا تَقَدَّمَ مِنْ ذَنْبِهِ