Sahih Muslim 370
Sahih Muslim · Book 3: The Book of Menstruation · Tayammum
Ibn Umar reported:
حَدَّثَنَا مُحَمَّدُ بْنُ عَبْدِ اللَّهِ بْنِ نُمَيْرٍ ، حَدَّثَنَا أَبِي ، حَدَّثَنَا سُفْيَانُ ، عَنِ الضَّحَّاكِ بْنِ عُثْمَانَ ، عَنْ نَافِعٍ ، عَنِ ابْنِ عُمَرَ ، أَنَّ رَجُلاً، مَرَّ وَرَسُولُ اللَّهِ صلى الله عليه وسلم يَبُولُ فَسَلَّمَ فَلَمْ يَرُدَّ عَلَيْهِ .
A person happened to pass by the Messenger of Allah (ﷺ) when he was making water and saluted him, but he did not respond to his salutation.