He divorced her with three pronouncements of divorce in the presence of the Messenger of Allah ﷺ, and the Messenger of Allah ﷺ put it into effect. What he did before the Prophet ﷺ became established practice.Sahl said, "I witnessed this in the presence of the Messenger of Allah ﷺ." The practice thereafter became settled regarding the Mutalaineen, that they are separated and never come together again.
فطلقها ثلاث تطليقات عند رسول الله ﷺ فأنفذه رسول الله ﷺ. وكان ما صنع عند النبي ﷺ سنة. قال سهل: حضرت هذا عند رسول الله ﷺ فمضت السنة بعد في المتلاعنين أن يفرق بينهما، ثم لا يجتمعان أبدا.
Abu Dawud narrated it (2250), and through his route Bayhaqi (7/401) narrated it from Ahmad bin Amr bin Sarh, who said, "Ibn Wahb told us, from Iyad bin Abdullah Fihri and others, from Ibn Shihab, from Sahl bin Saad," in his account, and he related it.Its chain is hasan because of Iyad bin Abdullah Fihri, who is closer to being daif than to being reliable. Abu Salih said, "He is firmly established, he has a great standing in Madinah, but there is something questionable in his hadith." Ibn Hibban deemed him reliable, and Ibn Shahin mentioned him in Thiqat. Yahya bin Main, Bukhari, and Abu Hatim criticized him, but he was corroborated by others.Bayhaqi said (7/400), Uzai narrated it, from Zubaydi, from Zuhri, from Sahl bin Saad, and in it he mentioned, "So they invoked mutual curses upon each other, and the Messenger of Allah ﷺ separated them," and he said, "They will never be reunited."