Arabic (Original)
حَدَّثَنَا عَبَّادُ بْنُ عَبَّادٍ الْمُهَلَّبِيُّ عَنْ مُحَمَّدِ بْنِ عَمْرٍو عَنْ أَبِي سَلَمَةَ عَنْ أَبِي هُرَيْرَةَ عَنْ النَّبِيِّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ أَنَّهُ قَالَ إِنَّمَا الْإِمَامُ لِيُؤْتَمَّ بِهِ فَإِذَا كَبَّرَ فَكَبِّرُوا وَإِذَا رَكَعَ فَارْكَعُوا وَإِذَا قَالَ سَمِعَ اللَّهُ لِمَنْ حَمِدَهُ فَقُولُوا رَبَّنَا لَكَ الْحَمْدُ فَإِذَا صَلَّى جَالِسًا فَصَلُّوا جُلُوسًا أَجْمَعِينَ.
English Translation
Abbad ibn Abbad al-Muhallabi told us, from Muhammad ibn Amr, from Abu Salamah, from Abu Hurayrah, from the Prophet, peace and blessings be upon him, that he said: "The imam is appointed only to be followed; so when he says the takbir, say the takbir, and when he bows, bow, and when he says 'Allah hears whoever praises Him,' say 'Our Lord, to You belongs praise,' and if he prays sitting, then all of you pray sitting."