From Sahih Bukhari (Hadith 6025):
Narrated Anas bin Malik:A bedouin urinated in the mosque and the people ran to (beat) him. Allah's Messenger (ﷺ) said, "Do not interrupt his urination (i.e. let him finish)." Then the Prophet (ﷺ) asked for a tumbler of water and poured the water over the place of urine
Reference: Bukhari 6025