حَدَّثَنَا أَحْمَدُ بْنُ عَبْدَةَ، أَنْبَأَنَا حَمَّادُ بْنُ زَيْدٍ، حَدَّثَنَا ثَابِتٌ، عَنْ أَنَسٍ، أَنَّ أَعْرَابِيًّا، بَالَ فِي الْمَسْجِدِ فَوَثَبَ إِلَيْهِ بَعْضُ الْقَوْمِ فَقَالَ رَسُولُ اللَّهِ ـ صلى الله عليه وسلم ـ ‏"‏ لاَ تُزْرِمُوهُ ‏"‏ ‏.‏ ثُمَّ دَعَا بِدَلْوٍ مِنْ مَاءٍ فَصَبَّ عَلَيْهِ ‏.‏

It was narrated from Anas bin Malik that: A Bedouin urinated in the mosque, and some of the people rushed at him. The Messenger of Allah said: "Do not interrupt him." Then he called for a bucket of water and poured it over (the urine). Translation Not Available

Book Ref: Sunan Ibn Majah Book 1 Hadith 528
Web Ref:  Sunan Ibn Majah Vol 1 Book 1 Hadith 528