Command him to take her back, then divorce her when she is pure or she is pregnant.
Sahih Muslim Book 18, Hadith 8
← Previous Hadith I took her back, and counted this pronouncement of divorce (as valid) with which I divorced her.

Sahih Muslim Book 18, Hadith 7 Next Hadith → Command him to take her back until she is pure and then she enters the second menses and then becomes pure. Then either divorce her (finally) or retain her.

Sahih Muslim Book 18, Hadith 9