Umm Qais daughter of Mihsan reported that she came to the Messenger of Allah (ﷺ) with her little son who had not attained the age of eating food. The Messenger of Allah (ﷺ) seated him in his lap, and he urinated on his clothe. He sent for water and sprayed it (over his clothe) and did not wash it.
Source: sunnah.com
Other translations
Arabic
حَدَّثَنَا عَبْدُ اللَّهِ بْنُ مَسْلَمَةَ الْقَعْنَبِيُّ، عَنْ مَالِكٍ، عَنِ ابْنِ شِهَابٍ، عَنْ عُبَيْدِ اللَّهِ بْنِ عَبْدِ اللَّهِ بْنِ عُتْبَةَ بْنِ مَسْعُودٍ، عَنْ أُمِّ قَيْسٍ بِنْتِ مِحْصَنٍ، أَنَّهَا أَتَتْ بِابْنٍ لَهَا صَغِيرٍ لَمْ يَأْكُلِ الطَّعَامَ إِلَى رَسُولِ اللَّهِ صلى الله عليه وسلم فَأَجْلَسَهُ رَسُولُ اللَّهِ صلى الله عليه وسلم فِي حِجْرِهِ فَبَالَ عَلَى ثَوْبِهِ فَدَعَا بِمَاءٍ فَنَضَحَهُ وَلَمْ يَغْسِلْهُ .
sunnah.com