The Prophet ﷺ said, "The Imam is to be followed. Say the Takbir when he says it; bow if he bows; if he says 'Samiʿa l-lahu liman hamidah', say, ' Rabbana wa laka l-hamd', prostrate if he prostrates and pray sitting altogether if he prays sitting."  

قَالَ النَّبِيُّ ﷺ إِنَّمَا جُعِلَ الإِمَامُ لِيُؤْتَمَّ بِهِ فَإِذَا كَبَّرَ فَكَبِّرُوا وَإِذَا رَكَعَ فَارْكَعُوا وَإِذَا قَالَ سَمِعَ اللَّهُ لِمَنْ حَمِدَهُ فَقُولُوا رَبَّنَا وَلَكَ الْحَمْدُ وَإِذَا سَجَدَ فَاسْجُدُوا وَإِذَا صَلَّى جَالِسًا فَصَلُّوا جُلُوسًا أَجْمَعُونَ  

[Machine] "On the authority of the Prophet ﷺ , he said: When the Imam says Allahu Akbar (Allah is the Greatest), you should also say Allahu Akbar. When he bows down, you should also bow down, and when he prostrates, you should also prostrate, and when he prays sitting down, you should also pray sitting down."  

عَنِ النَّبِيِّ ﷺ قَالَ إِذَا كَبَّرَ الْإِمَامُ فَكَبِّرُواوَإِذَا رَكَعَ فَارْكَعُوا وَإِذَا سَجَدَ فَاسْجُدُوا وَإِذَا صَلَّى جَالِسًا فَصَلُّوا جُلُوسًا  

[Machine] "On the authority of the Messenger of Allah ﷺ, he said: "When the Imam says 'Allahu Akbar', say 'Allahu Akbar' as well. And when he bows, bow with him. And when he prostrates, prostrate with him. And when he raises his head from bowing, raise your head as well. And if he prays while sitting, then pray sitting all together.""  

عَنْ رَسُولِ اللهِ ﷺ قَالَ «إِذَا كَبَّرَ الْإِمَامُ فَكَبِّرُوا وَإِذَا رَكَعَ فَارْكَعُوا وَإِذَا سَجَدَ فَاسْجُدُوا وَإِذَا رَفَعَ رَأْسَهُ مِنَ الرُّكُوعِ فَارْفَعُوا وَإِنْ صَلَّى جَالِسًا فَصَلُّوا جُلُوسًا أَجْمَعِينَ»  

"إذا كبَّرَ الإِمامُ فَكَبِّروا، وإذا ركعَ فارْكعُوا، وإذا سَجَد فاسْجُدوا، وإذا رفعَ رأسهَ مِنَ الرّكوعِ فارْفَعوا وإنْ صلَّى جالسًا فصَلُّوا جُلوسًا أجمعين".  

"إِنَّما الإِمَامُ ليُؤْتَمَّ به، فإذا كبَّرَ فكَبَّروا، وَإذا رَكعَ فارْكعُوا، وإِذا سَجَدَ فاسْجُدُوا وَإذا صَلَّى جالسا فصَلُّوَا جُلُوسًا أَجْمَعَون ".