If he prays without wudoo’ by mistake, he has to repeat his prayer

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Forgetting to sit for tashahhud between the second and third raka’ah
If the imam says one tasleem, is it permissible for the one who is praying behind him to say two?

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Related Answers:
He stood up to make up what he had missed the prayer when the imam had not yet completed his salaam at the end of the prayer
Wishing for death because of intense distress
When is it permissible for a person to pray sitting in obligatory prayers?
Forgetting to sit for tashahhud between the second and third raka’ah
If the imam says one tasleem, is it permissible for the one who is praying behind him to say two?

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