It wasnarrated that Abu Hurairah said:
The Messenger of Allah (ﷺ)said:"When the reciter says Amin, then say Amin, for if a person'sAmincoincides with the Amin of the angels, his previous sins will beforgiven." (DE)
English reference (DE): Vol. 1, Book 5, Hadith 852 (DE)
Arabic reference (DE): Book 5, Hadith 901 (DE)