An Arabi came and urinated in a corner of the mosque. The people rebuked him, but the Prophet ﷺ told them to leave him alone. When he had finished urinating, the Prophet ﷺ ordered a bucket of water to be brought and poured over the spot.
جاء أعرابي فبال في طائفة المسجد، فزجره الناس، فنهاهم النبي ﷺ، فلما قضى بوله أمر النبي ﷺ بذنوب من ماء، فأهريق عليه.
In another narration by Muslim, "While we were in the masjid with the Messenger of Allah ﷺ, a Bedouin came and stood up to urinate in the masjid. The companions of the Messenger of Allah ﷺ said, 'Stop! Stop!' He said, the Messenger of Allah ﷺ said, 'Do not interrupt him, leave him.' So they left him until he finished urinating. Then the Messenger of Allah ﷺ called him and said to him, "These masjids are not suitable for any of this urine or filth. They are only for the remembrance of Allah , for prayer, and for recitation of the Quran," or words to that effect, as the Messenger of Allah ﷺ said. He said, then he ordered a man from the people, who brought a bucket of water and poured it over the spot.His saying "fashannahu," with the dotted shin, means he poured it over it from every side, sprinkling it over it. In most narrations of Sahih Muslim it appears as "fasannahu," with the undotted sin. It is said, "sanantu al-ma ala al-thawb," and "ala al-ard," and the like, meaning you poured it over it.His saying, "in a part of the masjid," means a side of the masjid.The prohibition against urinating in the masjid also appears in what Abu Dawud narrated in Marasil (14), from Muslim bin Ibrahim, who said, Shubah narrated to us, from Umarah, from Abu Majliz, that the Prophet ﷺ ordered Umar to forbid urinating toward the qiblah of the masjid. Its narrators are trustworthy.Abu Dawud also narrated it in Marasil (3), from Hisham bin Khalid, who said, Walid narrated to us, from Ibn Jabir, from Makhul, who said, the Messenger of Allah ﷺ forbade urinating at the doors of masjids. Walid is Ibn Muslim, who conceals defects in transmission, and here he transmitted using "an" without stating direct hearing. However, one of these two narrations strengthens the other, though this does not raise it to the status of a fully connected chain.