Hadith 9682

حَدَّثَنَا مُحَمَّدُ بْنُ عُبَيْدٍ ، قَالَ : حَدَّثَنَا الْأَعْمَشُ ، عَنْ أَبِي صَالِحٍ ، عَنْ أَبِي هُرَيْرَة , قَالَ : " كَانَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ يُعَلِّمُنَا أَنْ لَا نُبَادِرَ الْإِمَامَ بِالرُّكُوعِ وَالسُّجُودِ ، وَإِذَا كَبَّرَ فَكَبِّرُوا ، وَإِذَا سَجَدَ فَاسْجُدُوا ، وَإِذَا قَالَ : غَيْرِ الْمَغْضُوبِ عَلَيْهِمْ وَلا الضَّالِّينَ سورة الفاتحة آية 7 , فَقُولُوا : آمِينَ ، فَإِذَا وَافَقَ كَلَامَ الْمَلَائِكَةِ ، غُفِرَ لِمَنْ فِي الْمَسْجِدِ ، وَإِذَا قَالَ : سَمِعَ اللَّهُ لِمَنْ حَمِدَهُ ، فَقُولُوا : رَبَّنَا لَكَ الْحَمْدُ " .
It is narrated from the previous chain that the Noble Prophet (peace and blessings be upon him) used to teach us not to go ahead of the imam in bowing and prostration, and that when he says the takbeer, you should also say the takbeer; when he prostrates, you should also prostrate; when he says "ghayril maghdubi 'alayhim wa la-d-dallin," you should say "Ameen," because if a person's "Ameen" coincides with that of the angels, then by its blessing, all the people present in the mosque are forgiven. And when he says "Sami' Allahu liman hamidah," you should say "Rabbana lakal hamd."
Hadith Reference مسند احمد / مسند المكثرين من الصحابة / 9682
Hadith Grading حکم دارالسلام: إسناده صحيح، خ: 782، م: 415