Al-Muwatta de Malik, 194

Abou Houraira a rapporté que l'Envoyé d'Allah (salallahou alayhi wa salam) r (Sur lui la grâce et la paix d'Allah) a dit: «quand l'imam récite «Non pas, (le chemin) de ceux qui encourent Ta colère ni celui des égarés», dites: «Amin», car celui qui le dit en même temps que les anges, ses fautes lui seront effacées»

Yahya related to me from Malik from Sumayy, the mawla of Abu Bakr, from Abu Salih as Samman, from Abu Hurayra that the Messenger of Allah, may Allah bless him and grant him peace, said, "When the imam has said, 'not of those with whom You are angry nor of those who are in error,' say 'Amin', for the previous wrong actions of the one whose utterance coincides with that of the angels, are forgiven him