Sahih Muslim 286a
Sahih Muslim · Book 2: The Book of Purification · The ruling on the urine of a nursing infant and how to wash it
A'isha, the wife of the Apostle (ﷺ) said:
حَدَّثَنَا أَبُو بَكْرِ بْنُ أَبِي شَيْبَةَ ، وَأَبُو كُرَيْبٍ قَالاَ حَدَّثَنَا عَبْدُ اللَّهِ بْنُ نُمَيْرٍ ، حَدَّثَنَا هِشَامٌ ، عَنْ أَبِيهِ ، عَنْ عَائِشَةَ ، زَوْجِ النَّبِيِّ صلى الله عليه وسلم أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم كَانَ يُؤْتَى بِالصِّبْيَانِ فَيُبَرِّكُ عَلَيْهِمْ وَيُحَنِّكُهُمْ فَأُتِيَ بِصَبِيٍّ فَبَالَ عَلَيْهِ فَدَعَا بِمَاءٍ فَأَتْبَعَهُ بَوْلَهُ وَلَمْ يَغْسِلْهُ .
Babies were brought to the Messenger of Allah (ﷺ) and he blessed them, and after having chewed (something, e. g. dates or any other sweet thing) he rubbed there with their soft palates. A baby was brought to him and he passed water over him (over his garment), so he asked water to be brought and sprinkled it, but he did not wash it.