If husband gives three irrevocable talak to wife but want to get her back and arrange tahleel marriage to get her my question is 1: as a result he arrange the marriage, will he become unlawful for his ex wife permanently? Or he can remarry her after a valid marriage and divorce of his ex wife. Please answer according to 4madhab in islam.

All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.

First of all, you should know that it is impermissible for a husband who has irrevocably divorced his wife to seek a Muhallil (a man who marries an irrevocably divorced woman with the intention of divorcing her so that she can remarry her ex-husband). The majority of jurists held that Tahleel marriage (one intended for making an irrevocably divorced woman lawful for her ex-husband) is invalid, and this is the preponderant opinion in this regard, as evidenced by the Hadeeth narrated on the authority of ‘Uqbah ibn ‘Aamir who related that the Messenger of Allah said: “Shall I not inform you of the borrowed billy-goat (from among men)?” They said: “Yes, O Messenger of Allah!” He said: “It is the Muhallil: May Allah curse the Muhallil and the Muhallal lahu (a husband who hires a man to marry his irrevocably divorced wife only to make her lawful for him).” [Ibn Maajah] Moreover, it was narrated that ‘Umar said: “Were a Muhallil and Muhallal lahu to be brought to me, I would stone them both.” [‘Abd Ar-Razzaaq in Al-Musannaf, and others] However, Abu Haneefah held that Tahleel marriage is valid and the wife becomes lawful for her ex-husband on account of such marriage, but the preponderant opinion in this regard is that of the majority of scholars, as mentioned above, given the strength of its supportive evidence.

We did not find any statement of any of the jurists of the four Fiqh schools or others stating that Tahleel marriage renders a woman permanently unlawful for her ex-husband. Therefore, if another man marries her in a genuine marriage (not a Tahleel marriage), consummated the marriage with her, and he then happened to divorce her, it is permissible for her first husband to marry her.

Allah Knows best.