It wasnarrated from Abu Hurairah that the Messenger of Allah (ﷺ)said:
"When the reciter says Amin, then say Amin, for the angels sayAmin,and if a person's Amin coincides with the Amin of the angels,hisprevious sins will be forgiven." (DE)
English reference (DE): Vol. 1, Book 5, Hadith 851 (DE)
Arabic reference (DE): Book 5, Hadith 900 (DE)