An imam who, after the closing salam, remembers that he prayed without ablution; what is the ruling for the imam and what is the ruling for the congregation?

The questioner : A man led a group in prayer, and after the closing salam, he remembered that he had prayed without ablution; what is the ruling for the imam and for the congregation? And is it obligatory for the imam to inform the congregation that he prayed without ablution?

The Shaykh : The answer is that it is not obligatory for the imam to inform the congregation that he prayed without ablution, so their prayer is valid. As for him, he must repeat it. This is what 'Umar ibn al-Khattab did in his time, and no one objected to him.