"The Messenger of Allah ﷺ said: 'When the Imam says: Not (the way) of those who earned Your anger, nor of those who went astray, say: 'Amin' for the angels say Amin and the Imam says Amin, and if a person's Amin coincides with the Amin of the angels, his previous sins will be forgiven.'" (Using translation from Nasāʾī 927)
قَالَ رَسُول الله ﷺ إِذَا قَالَ الْإِمَام {غَيْر الْمَغْضُوب عَلَيْهِم وَلَا الضآلين} فَقُولُوا آمِين فَإِن الْمَلَائِكَة تَقُول آمِين وَإِن الْإِمَام يَقُول آمِين فَمَن وَافَق تَأْمِينُه تَأْمِين الْمَلَائِكَة غَفَر لَه مَا تَقَدَّم مِنْ ذَنْبِه