Sahih Bukhari Volume 1, Book 4, Hadith 220

حَدَّثَنَا أَبُو الْيَمَانِ، قَالَ أَخْبَرَنَا شُعَيْبٌ، عَنِ الزُّهْرِيِّ، قَالَ أَخْبَرَنِي عُبَيْدُ اللَّهِ بْنُ عَبْدِ اللَّهِ بْنِ عُتْبَةَ بْنِ مَسْعُودٍ، أَنَّ أَبَا هُرَيْرَةَ، قَالَ قَامَ أَعْرَابِيٌّ فَبَالَ فِي الْمَسْجِدِ فَتَنَاوَلَهُ النَّاسُ، فَقَالَ لَهُمُ النَّبِيُّ صلى الله عليه وسلم ‏"‏ دَعُوهُ وَهَرِيقُوا عَلَى بَوْلِهِ سَجْلاً مِنْ مَاءٍ، أَوْ ذَنُوبًا مِنْ مَاءٍ، فَإِنَّمَا بُعِثْتُمْ مُيَسِّرِينَ، وَلَمْ تُبْعَثُوا مُعَسِّرِينَ ‏"

Narrated By Abu Huraira : A Bedouin stood up and started making water in the mosque. The people caught him but the Prophet ordered them to leave him and to pour a bucket or a tumbler of water over the place where he had passed the urine. The Prophet then said, "You have been sent to make things easy and not to make them difficult."