وَحَدَّثَنَا قُتَيْبَةُ بْنُ سَعِيدٍ، حَدَّثَنَا حَمَّادٌ، - وَهُوَ ابْنُ زَيْدٍ - عَنْ ثَابِتٍ، عَنْ أَنَسٍ، أَنَّ أَعْرَابِيًّا، بَالَ فِي الْمَسْجِدِ فَقَامَ إِلَيْهِ بَعْضُ الْقَوْمِ فَقَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم ‏"‏ دَعُوهُ وَلاَ تُزْرِمُوهُ ‏"‏ ‏.‏ قَالَ فَلَمَّا فَرَغَ دَعَا بِدَلْوٍ مِنْ مَاءٍ فَصَبَّهُ عَلَيْهِ ‏.‏

Anas reported: A Bedouin urinated in the mosque. Some of the persons stood up (to reprimand him or to check him from doing so), but the Messenger of Allah (PBUH) said: Leave him alone; don't interrupt him. He (the narrator) said: And when he had finished, he called for a bucket of water and poured it over. Translation Not Available

Book Ref: Sahih Muslim Book 2 Hadith 557
Web Ref:  Sahih Muslim Book 2 Hadith 284a