Sahl bin Sa’d (may Allah be pleased with him) narrated that I saw a husband and wife who invoked mutual cursing (li’an) before the Prophet (peace be upon him), and at that time I was fifteen years old. Then he narrated a long hadith, but did not preserve it as accurately as the others.
Hadith Referenceمسند الإمام الشافعي / كتاب اللعان / 1340
Hadith Takhrijاخرجه البخاري، الحدود، باب من اظهر الفاحشة واللطخ والتهمة بغير بنية (6854)۔