“I heard the Messenger of Allah (ﷺ) saying ‘Amin’ after he said, ‘nor of those who went astray.’
Sunan Ibn Majah Book 5, Hadith 52
← Previous Hadith “The people stopped saying Amin, but when the Messenger of Allah (ﷺ) said ‘Not (the way) of those who earned Your Anger, nor of those who went astray’ he would say Amin, until the people in the first row could hear it, and the mosque would shake with it.

Sunan Ibn Majah Book 5, Hadith 51 Next Hadith → “I performed prayer with the Prophet (ﷺ) and when he said: ‘Nor of those who went astray’, he said Amin and we heard that from him.”

Sunan Ibn Majah Book 5, Hadith 53