(76) باب الرَّجْعَةِ
Ibn 'Umar said:
"I divorced my wife when she was menstruating. 'Umar went to the Prophet and told him about that. The Prophet said: 'Tell him to take her back, then when she becomes pure, if he wants to, let him divorce her.'" I said to Ibn 'Umar: "Did that count as one divorce?" He said: "Why not? What do you think if some becomes helpless and behaves foolishly."
Reference: Sunan an-Nasa'i 3555
In-book reference: Book 27, Hadith 169
English translation: Vol. 4, Book 27, Hadith 3585