سنن النسائي

It was narrated that Yunus bin Jubair said: "I said to Ibn 'Umar: 'A man divorced his wife while she was menstruating.' He said: 'Do you know 'Abdullah bin 'Umar? He divorced his wife when she was menstruating, and 'Umar went to the Prophet (ﷺ) and asked him about that, and he told him to take her back then wait for the right time.' I said to him: 'Was that divorce counted?' He said: 'Be quiet! What do you think if some becomes helpless and behaves foolishly?'"