All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu ʻalayhi wa sallam, is His slave and Messenger.
Whenever a man divorces his wife thrice she completely separates from him and he cannot take her back unless she marries another man. Allaah Says (what means): {And if he has divorced her (the third time), then she is not lawful unto him thereafter until she has married another husband. Then, if the other husband divorces her, it is no sin on both of them that they reunite, provided they feel that they can keep the limits ordained by Allaah….}[Quran 2:230]
Ibn Abbas said: “A husband was more entitled to take his wife back even if he had divorced her thrice but this ruling was abrogated by this verse: {And if he has divorced her (the third time), then she is not lawful unto him thereafter until she has married another husband. Then, if the other husband divorces her, it is no sin on both of them that they reunite, provided they feel that they can keep the limits ordained by Allaah.}.”
The second marriage should be established with true intention of getting married and not just in order to make the wife [the woman] Halaal (lawful) for her first husband. Marrying only to make the wife halal for her husband is a major sin. This is what the Muhallil (the man who marries a woman just in order to make her lawful to her first husband) does. Nikah with such an intention is not valid according to the most correct opinion.
Ibn Maajah reported from Uqbah Ibn Aamir that the Prophet said: “Shall I tell you who is the borrowed breading bull (Muhallil)? They said: 'Please do, Messenger of Allaah. He said: “That is the Muhallil. May Allaah curse the Muhallil and the one who seeks his services.”
Thus, marriage with this intention is not permitted even if it is performed in presence of the guardian and 2 witnesses and the woman does not become Halal for her previous husband; rather, it is considered Zina as reported from Umar , may Allaah be pleased with him. Imam al-Hakim narrated from Umar that he said, “We used to consider it (Nikah of Muhallil) Zina in the period of the Prophet . ”
Ibn Abi Shaibah reported from Umar that he said, 'If a Muhallil and the one for whom Halalah is done were brought to me I would stone them both until death'.
Allaah knows best.