He divorced his wife while she was menstruating, so Umar went to the Prophet ﷺ and asked him for a ruling.The Prophet ﷺ said, "Tell Abdullah to take her back and keep her until she becomes pure from this menstrual period, then menstruates again. When she becomes pure, let him either divorce her before having intercourse with her or retain her. That is the waiting period during which Allah has commanded that women be divorced."
حدثنا يحيى عن عبيد الله أخبرني نافع
أنه طلق امرأته وهي حائض فأتى عمر النبي ﷺ فاستفتاه فقال مر عبد الله فليراجعها حتى تطهر من حيضتها هذه ثم تحيض حيضة أخرى فإذا طهرت فليفارقها قبل أن يجامعها أو ليمسكها فإنها العدة التي أمر أن تطلق لها النساء