(10) باب نَسْخِ الْمُرَاجَعَةِ بَعْدَ التَّطْلِيقَاتِ الثَّلاَثِ
Narrated Abdullah ibn Abbas:
Divorced women shall wait concerning themselves for three monthly periods. Nor is it lawful for them to hide what Allah hath created in their wombs. This means that if a man divorced his wife he had the right to take her back in marriage though he had divorced her by three pronouncements. This was then repealed (by a Qur'anic verse). Divorce is only permissible twice.
Reference: Sunan Abi Dawud 2195
In-book reference: Book 13, Hadith 21
English translation: Book 12, Hadith 2190