Sahih al-Bukhari 269
Sahih al-Bukhari · Book 5: Bathing (Ghusl) · The washing away of emotional urethral discharge and performing ablution after it
Narrated `Ali:
حَدَّثَنَا أَبُو الْوَلِيدِ ، قَالَ حَدَّثَنَا زَائِدَةُ ، عَنْ أَبِي حَصِينٍ ، عَنْ أَبِي عَبْدِ الرَّحْمَنِ ، عَنْ عَلِيٍّ ، قَالَ كُنْتُ رَجُلاً مَذَّاءً فَأَمَرْتُ رَجُلاً أَنْ يَسْأَلَ النَّبِيَّ صلى الله عليه وسلم لِمَكَانِ ابْنَتِهِ فَسَأَلَ فَقَالَ " تَوَضَّأْ وَاغْسِلْ ذَكَرَكَ " .
I used to get emotional urethral discharge frequently. Being the son-in-law of the Prophet (ﷺ) I requested a man to ask him about it. So the man asked the Prophet (ﷺ) about it. The Prophet (ﷺ) replied, "Perform ablution after washing your organ (penis)."