Sahih al-Bukhari 4842

Arabic

وَعَنْ عُقْبَةَ بْنِ صُهْبَانَ، قَالَ سَمِعْتُ عَبْدَ اللَّهِ بْنَ الْمُغَفَّلِ الْمُزَنِيِّ، فِي الْبَوْلِ فِي الْمُغْتَسَلِ‏.‏

English translation

Abdullah bin Al-Mughaffal Al-Muzani also said:"The Prophet (ﷺ) also forbade urinating at the place where one takes a bath

Reference: Sahih al-Bukhari 4842, Book of Prophetic Commentary on the Qur'an (Tafseer of the Prophet (pbuh)). English translation by Dr. Muhammad Muhsin Khan.