Sunan Ibn Majah 876
سنن ابن ماجه#876Sahihحَدَّثَنَا هِشَامُ بْنُ عَمَّارٍ، حَدَّثَنَا سُفْيَانُ، عَنِ الزُّهْرِيِّ، عَنْ أَنَسِ بْنِ مَالِكٍ، . أَنَّ رَسُولَ اللَّهِ ـ صلى الله عليه وسلم ـ قَالَ " إِذَا قَالَ الإِمَامُ سَمِعَ اللَّهُ لِمَنْ حَمِدَهُ . فَقُولُوا رَبَّنَا وَلَكَ الْحَمْدُ " .
It was narrated from Anas bin Malik that the Messenger of Allah (ﷺ) said:“When the Imam says: ‘Sami’ Allahu liman hamidah (Allah hears those who praise Him),’ say: ‘Rabbana wa lakal-hamd (O our Lord, to You is the praise).’”
Scholarly Authentication
The label above is the grade most of these scholars gave — one dissenting opinion no longer speaks for all of them. If any scholar calls a narration fabricated, that verdict is shown instead, whatever the others say. Each scholar's own wording:
In-book reference: 5:74