He joined the congregation to pray Maghrib, and did not realize that the imaam was praying 'Ishaa'

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The Imam misses Fajr prayer and argues with them about money issues
Praying behind ibaadis and innovators

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Related Answers:
Where should a woman stand when leading other women in prayer, and the preference for women to pray in their homes
One who comes into the mosque joining one who has stood up to complete the rak’ahs he missed
Non-circumcised man leading prayers
The Imam misses Fajr prayer and argues with them about money issues
Praying behind ibaadis and innovators

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