Sahih al-Bukhari 6355
Narrated `Aisha:
The boys used to be brought to the Prophet (ﷺ) and he used to invoke for Allah's blessing upon them. 
Once an infant was brought to him and it urinated on his clothes. He asked for water and poured it 
over the place of the urine and did not wash his clothes.
حَدَّثَنَا عَبْدَانُ، أَخْبَرَنَا عَبْدُ اللَّهِ، أَخْبَرَنَا هِشَامُ بْنُ عُرْوَةَ، عَنْ أَبِيهِ، عَنْ عَائِشَةَ ـ رضى الله عنها ـ قَالَتْ كَانَ النَّبِيُّ صلى الله عليه وسلم يُؤْتَى بِالصِّبْيَانِ فَيَدْعُو لَهُمْ، فَأُتِيَ بِصَبِيٍّ فَبَالَ عَلَى ثَوْبِهِ، فَدَعَا بِمَاءٍ فَأَتْبَعَهُ إِيَّاهُ، وَلَمْ يَغْسِلْهُ‏.‏