What is the ruling regarding the prayers of a man who led people in prayer while in a state of major ritual impurity (janabah), and he only became aware of it after the 'Isha prayer? And what is the ruling regarding the prayer of those led by him? And what should he and they do?

Most jurists hold that a worshiper's knowledge of the imam's ritual impurity after the prayer is excusable, while the imam must repeat the prayer by consensus. The Hanbalis further detail that if only the worshiper is unaware of the imam's ritual impurity, and only the imam knows it, then all of them must repeat the prayer. However, if both the imam and all the worshipers are unaware of it, then the prayer of the worshipers alone is valid.

Therefore, if the imam leads the people in prayer while forgetting his state of ritual impurity (janabah), he must repeat all prayers by consensus. However, the congregants following him are not required to repeat their prayers, according to the well-known opinion, based on the Prophet's (peace be upon him) saying: "If a person in a state of ritual impurity (junub) leads the people in prayer, he must repeat his prayer, and the prayer of the people is complete."