The ruling on the prayer of the followers if the imam remembers that he was not in a state of ritual purity after the closing salam

Question:
He says: Honorable Shaykh, may Allah grant you success, if the imam discovers after the prayer that he was not in a state of ritual purity, does he inform the followers? And what is required of the followers?

Answer:
The followers owe nothing; their prayer is valid. If he did not know that he was not in a state of ritual purity until after he had finished the prayer, his prayer is not valid, and he must repeat it. As for the prayer of the followers, it is valid. However, if he knows while he is in the prayer that he is not in a state of ablution, it is not permissible for him to continue; he must leave, so he does not continue without ablution.