Maliks Muwatta Book 29, Hadith Number 1.
Section : The ‘Irrevocable’ Divorce.
Yahya related to me from Malik that he had heard that a man said to Abdullah ibn Abbas, “I have divorced my wife by saying I divorce you a hundred times. What do you think my situation is?” Ibn Abbas said to him, “She was divorced from you by three pronouncements, and by the ninety-seven, you have mocked the ayat of Allah.”