Sahih al-Bukhari 291

Muadh ibn Fadalah narrated to us, saying: Hisham narrated to us. (Another chain:) Abu Nuaym narrated to us, from Hisham, from Qatadah, from al-Hasan, from Abu Rafi, from Abu Hurayrah, from the Prophet (ﷺ), who said: “When a man sits between her four limbs and exerts himself, the full bath becomes obligatory.” Amr ibn Marzuq corroborated it from Shubah with the same wording. Musa said: Aban narrated to us, saying: Qatadah narrated to us; al-Hasan informed us of the same.