بُلُوغُ الْمَرَامِ
Bulugh al-Maram 1098
Marriage
وَعَنْ سَهْلِ بْنِ سَعْدٍ -فِي قِصَّةِ اَلْمُتَلَاعِنَيْنِ- قَالَ: { فَلَمَّا فَرَغَا مِنْ تَلَاعُنِهِمَا قَالَ: كَذَبْتُ عَلَيْهَا يَا رَسُولَ اَللَّهِ! إِنْ أَمْسَكْتُهَا, فَطَلَّقَهَا ثَلَاثًا قَبْلَ أَنْ يَأْمُرَهُ رَسُولُ اَللَّهِ - صلى الله عليه وسلم -} مُتَّفَقٌ عَلَيْهِ . [1] .
Narrated Sahl bin Sa'd (RA) concerning the story of the two (husband and wife) who invoked curses regarding one another: When they finished invoking curses regarding one another the man said, "I shall have lied against her, O Allah's Messenger (ﷺ) , if I keep her (as a wife)." He, then, pronounced her divorce three times, even before Allah's Messenger (ﷺ) commanded him to do so. [Agreed upon].
Sunnah.com reference: Book 8, Hadith 155