Sayyiduna Abu Hurairah (may Allah be pleased with him) said: The Messenger of Allah (peace and blessings of Allah be upon him) said: "When the reciter says «غَيْرِ الْمَغْضُوبِ عَلَيْهِمْ وَلَا الضَّالِّينَ» , then those who are behind him (the followers in prayer) should say Ameen, and if this Ameen coincides with that of those in the heavens, all his previous sins will be forgiven."