Abdullah bin Umar reported,

He divorced his wife while she was menstruating. Umar mentioned this to the Messenger of Allah ﷺ, so Umar went to the Messenger of Allah ﷺ and informed him. The Messenger of Allah ﷺ said, "Let him keep her back until she finishes this menstrual period, then menstruates again, then becomes pure. Then, if he wishes to divorce her, let him divorce her as Allah has commanded, and if he wishes to keep her, let him keep her."

حدثنا روح حدثنا محمد بن أبي حفصة

حدثنا ابن شهاب عن سالم عن أبيه

أنه طلق امرأته وهي حائض قال فذكر ذلك إلى عمر فانطلق عمر إلى رسول الله ﷺ فأخبره فقال رسول الله ﷺ ليمسكها حتى تحيض غير هذه الحيضة ثم تطهر فإن بدا له أن يطلقها فليطلقها كما أمره الله عز وجل وإن بدا له أن يمسكها فليمسكها