Sahih Bukhari

Narrated Qatada:Anas bin Malik said, ""The Prophet (ﷺ) used to visit all his wives in a round, during the day and night and they were eleven in number."" I asked Anas, ""Had the Prophet (ﷺ) the strength for it?"" Anas replied, ""We used to say that the Prophet (ﷺ) was given the strength of thirty (men)."" And Sa`id said on the authority of Qatada that Anas had told him about nine wives only (not eleven)