Question :
An Imam stood to offer a fifth Rak`ah in a four-Rak`ah prayer, and he was reminded to sit by those behind him, but he wouldn`t listen. What is the ruling on those who followed his lead knowingly and intentionally?
The Answer :
If the Imam stood to offer a fifth Rak`ah, those praying behind him shouldn`t have approved of that, and the prayer of those who did is considered null and void.