Is it permissible for the Imam to combine two prayers, whether for an excuse or without an excuse, citing as evidence the combining of prayers by the Prophet, may Allah bless him and grant him peace? And is it obligatory for the congregant to follow the Imam in combining prayers?

The Imam's act of combining prayers without a valid excuse is a grave and compounded error. His attempt to compel people to do so and his claim that it is the Sharia is ignorance, for combining two prayers without an excuse is among the major sins. The hadith of Ibn Abbas about the Prophet (peace be upon him) combining prayers without fear or rain was not absolutely without excuse; rather, it was due to illness or a need to alleviate hardship, or it was a figurative combination. Following this Imam in his combining of prayers without a valid excuse is impermissible, and he must be advised. If he does not heed the advice, then following him is not permissible.