Sunan an-Nasa'i 3415
سنن النسائي#3415SahihIt was narrated that Ibn 'Umar said:"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
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Abu GhuddahSahih Lighairihi
Al-AlbaniSahih
Zubair Ali ZaiSahih
In-book reference: 27:27