Ahmed bin Hafs bin 'Abdullah أحمد بن حفص بن عبد الله · The Book of Divorce

"Tell him to take her back until she menstruates again, then when she becomes pure, if he wants he may divorce her and if he wants he may keep her. This is the divorce that Allah has enjoined. Allah, the Mighty and Sublime, says: 'The divorce is twice, after that, either you retain her on reasonable terms or release her with kindness.'"