The Messenger of Allah ﷺ while teaching us (the principles of faith), said: Do not try to go ahead of the Imam, recite takbir when he recites it, and when he says: "Nor of those who err" you should say Amin, bow down when he bows down, and when he says: "Allah listens to him who praises Him" say: "O Allah, our Lord, to Thee be the praise".  

كَانَ رَسُولُ اللَّهِ ﷺ يُعَلِّمُنَا يَقُولُ لاَ تُبَادِرُوا الإِمَامَ إِذَا كَبَّرَ فَكَبِّرُوا وَإِذَا قَالَ وَلاَ الضَّالِّينَ فَقُولُوا آمِينَ وَإِذَا رَكَعَ فَارْكَعُوا وَإِذَا قَالَ سَمِعَ اللَّهُ لِمَنْ حَمِدَهُ فَقُولُوا اللَّهُمَّ رَبَّنَا لَكَ الْحَمْدُ  

“The Messenger of Allah ﷺ said: ‘The Imam has been appointed to be followed, so when he says Allahu Akbar, then say Allahu Akbar, when he recites, then listen attentively; when he says: Not (the way) of those who earned Your anger, nor of those who went astray,[1:7] then say Amin; when he bows then bow; when he says Sami’ Allahu liman hamidah (Allah hears those who praise Him), then say Allahumma Rabbana wa lakal-hamd (O Allah, our Lord, to You is the praise);” when he prostrates then prostrate; and if he prays sitting down then all of you pray sitting down.’”  

قَالَ رَسُولُ اللَّهِ ﷺ إِنَّمَا جُعِلَ الإِمَامُ لِيُؤْتَمَّ بِهِ فَإِذَا كَبَّرَ فَكَبِّرُوا وَإِذَا قَرَأَ فَأَنْصِتُوا وَإِذَا قَالَ {غَيْرِ الْمَغْضُوبِ عَلَيْهِمْ وَلاَ الضَّالِّينَ} فَقُولُوا آمِينَ وَإِذَا رَكَعَ فَارْكَعُوا وَإِذَا قَالَ سَمِعَ اللَّهُ لِمَنْ حَمِدَهُ فَقُولُوا اللَّهُمَّ رَبَّنَا وَلَكَ الْحَمْدُ وَإِذَا سَجَدَ فَاسْجُدُوا وَإِذَا صَلَّى جَالِسًا فَصَلُّوا جُلُوسًا أَجْمَعِينَ  

[Machine] The Messenger of Allah ﷺ used to teach us not to precede the imam in bowing and prostration. And when he (the imam) says "Allahu Akbar" (Allah is the Greatest), say "Allahu Akbar". And when he (the imam) prostrates, prostrate. And when he recites the verse "Not (the way) of those who incurred wrath upon themselves, nor of those who went astray" [Al-Fatiha 7], say "Ameen" (O Allah, accept our prayers), for when the words of the angels coincide with these words, the sins of those in the mosque are forgiven. And when he (the imam) says, "Allah hears whoever praises Him," say "Our Lord, to You belongs all praise."  

كَانَ رَسُولُ اللهِ ﷺ يُعَلِّمُنَا أَنْ لَا نُبَادِرَ الْإِمَامَ بِالرُّكُوعِ وَالسُّجُودِ وَإِذَا كَبَّرَ فَكَبِّرُوا وَإِذَا سَجَدَ فَاسْجُدُوا وَإِذَا قَالَ {غَيْرِ الْمَغْضُوبِ عَلَيْهِمْ وَلَا الضَّالِّينَ} [الفاتحة 7] فَقُولُوا آمِينَ فَإِنَّهُ إِذَا وَافَقَ كَلَامَ الْمَلَائِكَةِ غُفِرَ لِمَنْ فِي الْمَسْجِدِ وَإِذَا قَالَ سَمِعَ اللهُ لِمَنْ حَمِدَهُ فَقُولُوا رَبَّنَا لَكَ الْحَمْدُ  

“The Messenger of Allah ﷺ said: ‘The Imam has been appointed to be followed, so when he says Allahu Akbar, then say Allahu Akbar, when he recites, then listen attentively; when he says: Not (the way) of those who earned Your anger, nor of those who went astray,[1:7] then say Amin; when he bows then bow; when he says Sami’ Allahu liman hamidah (Allah hears those who praise Him), then say Allahumma Rabbana wa lakal-hamd (O Allah, our Lord, to You is the praise);” when he prostrates then prostrate; and if he prays sitting down then all of you pray sitting down.’” (Using translation from Ibn Mājah 846)   

أَنَّ رَسُولَ اللهِ ﷺ قَالَ إِنَّمَا الْإِمَامُ لِيُؤْتَمَّ بِهِ فَإِذَا كَبَّرَ فَكَبِّرُوا وَإِذَا قَرَأَ فَأَنْصِتُوا وَإِذَا قَالَ {وَلَا الضَّالِّينَ} [الفاتحة 7] فَقُولُوا آمِينَ وَإِذَا رَكَعَ فَارْكَعُوا وَإِذَا قَالَ سَمِعَ اللهُ لِمَنْ حَمِدَهُ فَقُولُوا رَبَّنَا وَلَكَ الْحَمْدُ وَإِذَا صَلَّى جَالِسًا فَصَلُّوا جُلُوسًا أَجْمَعُونَ  

[Machine] The Prophet ﷺ used to teach us not to preempt the Imam in bowing, and when he says "Allahu Akbar," say "Allahu Akbar," and when he says "not of those who have evoked [Your] anger or of those who are astray," say "Ameen." For when the words of the angels coincide with his words, the sins of those present in the mosque are forgiven. And when he prostrates, prostrate. And when he says "Allah hears whoever praises Him," say "Our Lord, and to You is the praise." And when he says "And when he prostrates," prostrate.  

كَانَ رَسُولُ اللهِ ﷺ يُعَلِّمُنَا أَنْ لَا تُبَادِرُوا الْإِمَامَ بِالرُّكُوعِ فَإِذَا كَبَّرَ فَكَبِّرُوا وَإِذَا قَالَ غَيْرِ الْمَغْضُوبِ عَلَيْهِمْ وَلَا الضَّالِّينَ فَقُولُوا آمِينَ فَإِنَّهُ إِذَا وَافَقَ كَلَامَ الْمَلَائِكَةِ غُفِرَ لِمَنْ فِي الْمَسْجِدِ وَإِذَا رَكَعَ فَارْكَعُوا وَإِذَا قَالَ سَمِعَ اللهُ لِمَنْ حَمِدَهُ فَقُولُوا رَبَّنَا وَلَكَ الْحَمْدُ وَإِذَا سَجَدَ فَاسْجُدُوا  

"لا تُبَادِرُوا الإِمَامَ، إِذَا كَبَّرَ فَكَبِّرُوا، وإِذَا قَال: وَلا الضَّالِّينَ فَقُولُوا: آمِين، وَإِذَا رَكعَ فَارْكَعُوا، وَإذَا قَال: سَمِعَ الله لِمَنْ حَمِدَهْ فَقُولُوا: اللَّهُمَّ رَبَّنَا وَلَكَ الْحَمْدُ، وَلا تَرْفَعُوا قَبْلهُ".  

"إِنَّما جعلَ الإِمامُ ليؤتَمَّ به، فإِذا كبَّر فكبِّروا، وإِذا قَرأ فأَنْصِتُوا، وإِذا قال، {غَيْرِ الْمَغْضُوبِ عَلَيْهِمْ وَلَا الضَّالِّينَ}، فقُولوا: آمين، وإذا رَكَعَ فاركعوا، وإذا قال: سمع اللَّه لمن حَمِدَهُ فقولوا: اللَّهُمَّ ربّنا ولك الحمد، وإذا سَجَدَ فاسْجُدُوا. وإِذا صلى جالسًا فصَلُّوا جلوسًا".