Sahih Muslim Book - 2, Hadith - 662

حَدَّثَنَا أَبُو بَكْرِ بْنُ أَبِي شَيْبَةَ وَأَبُو كُرَيْبٍ قَالَا حَدَّثَنَا عَبْدُ اللَّهِ بْنُ نُمَيْرٍ حَدَّثَنَا هِشَامٌ عَنْ أَبِيهِ عَنْ عَائِشَةَ زَوْجِ النَّبِيِّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ أَنَّ رَسُولَ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ كَانَ يُؤْتَى بِالصِّبْيَانِ فَيُبَرِّكُ عَلَيْهِمْ وَيُحَنِّكُهُمْ فَأُتِيَ بِصَبِيٍّ فَبَالَ عَلَيْهِ فَدَعَا بِمَاءٍ فَأَتْبَعَهُ بَوْلَهُ وَلَمْ يَغْسِلْهُ.

It was narrated from 'Aishah, the wife of the Prophet (s.a.w), that babies would be brought to the Messenger of Allah (s.a.w), and he would pray for blessing for them and put some soft, chewed dates in their mouths (Tahnik). A baby was brought to him and (the child) urinated on him. He called for some water and sprinkled it over the urine, but he did not wash it.