"A man passed by the Prophet ﷺ when he was urinating and greeted him with Salam, but he did not return his greeting."  

مَرَّ رَجُلٌ عَلَى النَّبِيِّ ﷺ وَهُوَ يَبُولُ فَسَلَّمَ عَلَيْهِ فَلَمْ يَرُدَّ عَلَيْهِ السَّلاَمَ