Sayyiduna Abu Hurairah (may Allah be pleased with him) narrates: The Prophet Muhammad (peace and blessings be upon him) ascended the pulpit and said: Ameen, Ameen, Ameen. It was asked, O Messenger of Allah! When you ascended the pulpit, you said Ameen, Ameen, Ameen; what is the reason for this? The Prophet Muhammad (peace and blessings be upon him) said: Jibreel came to me and said: Whoever finds the month of Ramadan and is not forgiven, then let him enter Hell, so may Allah (distance him from His mercy), you say Ameen, so I said Ameen. When someone finds his parents or one of them and does not treat them well, and after dying enters Hell, then may Allah (distance him from His mercy), you say Ameen, so I said Ameen. (Then Jibreel said:) Whoever hears your mention and does not send blessings upon you, and after dying enters Hell, then may Allah (distance him from His mercy), you say Ameen, so I said Ameen.
Hadith Referenceصحیح ابن حبان / كتاب الرقائق / 907
Hadith Gradingفضيلة الشيخ الإمام محمد ناصر الدين الألبانيحسن صحيح.فضيلة الشيخ العلّامة شُعيب الأرناؤوطإسناده حسن، محمد بن عمرو: هو ابن علقمة بن وقاص الليثي المدنى، قال الحافظ في "التقريب ": صدوق له أوهام، وباقي رجاله ثقات. أبو معمر هو: إسماعيل بن إبراهيم بن معمر الهذلي.