Hadith 10:6
Abu Bakr narrated to us, he said: Abdullah ibn Idris narrated to us, from Ubaydullah ibn Umar, from Nafi’, from Ibn Umar, who said: I divorced my wife while she was menstruating. Umar mentioned that to the Messenger of Allah (may Allah bless him and grant him peace), and he said: "Command him to take her back until she becomes pure, then she menstruates, then she becomes pure. Then, if he wishes, he may divorce her before he has intercourse with her, and if he wishes, he may keep her; for that is the waiting period which Allah commanded."
حدثنا أبو بكر قال نا عبد الله بن إدريس عن عبيد الله بن عمر عن نافع عن بن عمر قال طلقت امرأتي وهي حائض فذكر ذلك عمر لرسول الله صلى الله عليه وسلم فقال مره فليراجعها حتى تطهر ثم تحيض ثم تطهر ثم إن شاء طلقها قبل أن يجامعها وإن شاء أمسكها فإنها العدة التي قال الله