It is narrated from Sayyiduna Wa'il bin Hujr (may Allah be pleased with him) that he prayed with the Prophet (peace and blessings be upon him), and when he (peace and blessings be upon him) recited Surah al-Fatihah and said "Not of those who have earned [Your] anger, nor of those who are astray" [Al-Fatihah: 7], he said "Amin" and raised his voice with it.
Hadith Referenceالمعجم الكبير للطبراني / باب الواو / 18252