Yahya related to me from Malik from Yahya ibn Said from Abu Bakribn Hazm thatUmar ibn Abd al-Aziz had asked him what people said aboutthe 'irrevocable' divorce, and Abu Bakr had replied that Aban ibnUthman 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."
USC-MSA web (English) reference: Book 29, Hadith 3
Arabic reference: Book 29, Hadith 1155