Sahih al-Bukhari 179
صحيح البخاري#179SahihNarrated Zaid bin Khalid:I asked `Uthman bin `Affan about a person who engaged in intercourse but did no discharge. `Uthman replied, "He should perform ablution like the one for an ordinary prayer but he must wash his penis." `Uthman added, "I heard it from Allah's Messenger (ﷺ)." I asked `Ali Az-Zubair, Talha and Ubai bin Ka`b about it and they, too, gave the same reply. (This order was canceled later on and taking a bath became necessary for such cases)
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Every narration in Sahih al-Bukhari is accepted as Sahih (authentic) by the established status of the book.
In-book reference: 4:45