If the worshipper (ma'mum) says the taslim before the imam, either by mistake or intentionally, what is the ruling?

If the congregant (ma'mum) intentionally says the taslim (salutation) before the imam without a valid excuse, their prayer becomes invalid. However, if it was due to forgetfulness, they must return to the prayer and say the taslim after their imam; otherwise, their prayer becomes invalid for abandoning the obligation of following the imam. It is permissible to say the taslim before the imam for a valid excuse, such as:

1. The imam prolongs the prayer excessively beyond the Sunnah, as in the story of the man who left Mu'adh when he prolonged the prayer, and the Prophet, peace be upon him, did not rebuke him.

2. If the worshipper experiences vomiting, gas, or difficulty holding urine or stool, and it becomes difficult for them to remain with the imam.

3. If the congregant's prayer is shorter than the imam's prayer, such as someone praying Maghrib behind someone praying Isha; in this case, they may separate and say the taslim.