Arabic (Original)
وَبِإِسْنَادِهِ قَالَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ إِذَا كَبَّرَ الْإِمَامُ فَكَبِّرُوا وَإِذَا رَكَعَ فَارْكَعُوا وَإِذَا سَجَدَ فَاسْجُدُوا وَإِذَا صَلَّى جَالِسًا فَصَلُّوا جُلُوسًا.
English Translation
And with his chain: The Messenger of Allah (peace and blessings be upon him) said: "When the imam says the takbir, say the takbir; when he bows, bow; when he prostrates, prostrate; and when he prays sitting, pray sitting."