عَنْ أَبِي هُرَيْرَةَ رَضِيَ اللَّهُ عَنْهُ قَالَ: قَالَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَآلِهِ وَسَلَّمَ: ((إِنَّمَا جُعِلَ الْإِمَامُ لِيُؤْتَمَّ بِهِ، فَإِذَا كَبَّرَ فَكَبِّرُوا، وَإِذَا قَرَأَ فَأَنْصِتُوا))
Sayyiduna Abu Hurairah, may Allah be pleased with him, narrates that the Messenger of Allah, peace and blessings be upon him, said: The Imam is appointed only to be followed, so when he says the takbeer, you should also say the takbeer, and when he recites (the Qur'an), you should remain silent.