Nafi reported,

Ibn Umar divorced his wife while she was menstruating, so Umar asked the Prophet ﷺ about it. The Prophet instructed him to take her back, then leave her until she completed another menstrual cycle, then leave her until she became pure again, and then divorce her before touching her. He said, "That is the waiting period during which Allah commanded that women be divorced."Whenever Ibn Umar was asked about a man who divorced his wife while she was menstruating, he would reply, "As for me, I divorced her once or twice, and the Messenger of Allah ﷺ instructed me to take her back, then leave her until she completed another menstrual cycle, then leave her until she became pure, and then divorce her before touching her. But as for you, you divorced her three times. You have disobeyed Allah in the manner He commanded you to divorce your wife, and she is now separated from you."

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عن نافع

أن ابن عمر طلق امرأته تطليقة وهي حائض فسأل عمر النبي ﷺ فأمره أن يرجعها ثم يمهلها حتى تحيض حيضة أخرى ثم يمهلها حتى تطهر ثم يطلقها قبل أن يمسها قال وتلك العدة التي أمر الله عز وجل أن يطلق لها النساء فكان ابن عمر إذا سئل عن الرجل يطلق امرأته وهي حائض فيقول أما أنا فطلقتها واحدة أو اثنتين ثم إن رسول الله ﷺ أمره أن يرجعها ثم يمهلها حتى تحيض حيضة أخرى ثم يمهلها حتى تطهر ثم يطلقها قبل أن يمسها وأما أنت طلقتها ثلاثا فقد عصيت الله بما أمرك به من طلاق امرأتك وبانت منك