Ubaid bin 'Umayr bin Qatada عبيد بن عمير بن قتادة · The Book of Divorce

"The Prophet was asked about a man who divorced his wife three times, then another man married her and he closed the door and drew the curtain, then divorced her before consummating the marriage with her. He said: "She is not permissible for the first one (to remarry her) until the second one has had intercourse with her.""