and the followers [may continue] after he has removed the impurity. This is what the author’s words imply.

The correct view regarding this issue is that if both the imam and the followers are unaware of the impurity until the prayer is over, then all of their prayers are valid, for ignorance is an excuse for everyone. According to the stronger view, one who prays while contaminated by impurity, unaware of it, does not have to repeat the prayer. Likewise, if he knows of it but forgets to wash it away, then, according to the stronger view, his prayer is valid (1).

This clarifies the difference, according to the stronger view, between this case and the preceding one: if a worshipper is unaware that he is in a state of ritual impurity, he must repeat the prayer; but he does not have to repeat it if he is unaware of physical impurity. The difference between them is that purifying oneself from ritual impurity by ablution belongs to the category of performing what has been commanded, whereas avoiding physical impurity belongs to the category of refraining from what has been prohibited. Thus, if he does it unknowingly, its ruling does not apply to him.

Evidence for this stronger view is that “the Prophet, peace and blessings be upon him, once led his Companions in prayer while wearing his sandals. He then removed them, so the Companions removed their sandals as well. When he had finished, he asked them why they had removed their sandals. They said, ‘We saw you remove your sandals, so we removed ours.’ He replied, ‘Gabriel came to me and informed me that there was filth on them, so I removed them’” (2). This clearly shows that the Messenger, peace and blessings be upon him, had been wearing sandals contaminated with filth, yet he was unaware of it. Had the prayer been invalidated by ignorance, the Prophet, peace and blessings be upon him, would have begun his prayer anew.

Accordingly, if the imam becomes aware of the impurity during the prayer, then if