Maliks Muwatta Book 29, Hadith Number 3.

Section : The ‘Irrevocable’ Divorce.

Yahya related to me from Malik from Yahya ibn Said from Abu Bakr ibn Hazm that Umar ibn Abd al-Aziz had asked him what people said about the ‘irrevocable’ divorce, and Abu Bakr had replied that Aban ibn Uthman had clarified that it was declared only once. Umar ibn Abd al-Aziz said, “Even if divorce had to be declared a thousand times, the ‘irrevocable’ would use them all up. A person who says, ‘irrevocably’ has cast the furthest limit.”