954 – On the authority of Sahl ibn Saʿd al-Anṣārī (may Allah be pleased with him), in the story of the two spouses who invoked the mutual imprecation, he said: “When they had completed their imprecation, the man declared, ‘I have certainly lied about her, Messenger of Allah, if I keep her,’ and he then pronounced a triple divorce before the Messenger of Allah ﷺ had instructed him to do so.” Agreed upon.⦗1⦘

What is drawn from the ḥadith:
1 – Once the mutual imprecation (liʿān) is completed, a perpetual separation is established between the two spouses; no additional divorce or annulment is required, for this is the legal effect of liʿān.
2 – In this narration, the man who performed liʿān in the Prophet’s ﷺ presence said, to affirm his own truthfulness and reinforce his charge: “I would be lying about her, Messenger of Allah, if I were to keep her,” after which he issued a triple divorce before the Prophet ﷺ directed him to do so.
3 – Our jurists state that the separation becomes binding, with lifelong prohibition, immediately upon the completion of liʿān, even if the judge has not yet pronounced it. This is the position of the majority, because the separation results from liʿān itself, as recorded in Ṣaḥīḥ Muslim: “That is the separation between every couple who engage in mutual imprecation,” and in his words: “You have no path to her anymore.”
4 – Any divorce the husband pronounces after performing liʿān is null and without effect; he uttered it only out of intense anger and to further assert the truth of his accusation against her.