The Book of Purification and its Sunnah
1/27. Chapter:
A man who is greeted while he is urinating
Sunan Ibn Majah
حَدَّثَنَا عَبْدُ اللَّهِ بْنُ سَعِيدٍ، وَالْحُسَيْنُ بْنُ أَبِي السَّرِيِّ الْعَسْقَلاَنِيُّ، قَالاَ حَدَّثَنَا أَبُو دَاوُدَ، عَنْ سُفْيَانَ، عَنِ الضَّحَّاكِ بْنِ عُثْمَانَ، عَنْ نَافِعٍ، عَنِ ابْنِ عُمَرَ، قَالَ مَرَّ رَجُلٌ عَلَى النَّبِيِّ ـ صلى الله عليه وسلم ـ وَهُوَ يَبُولُ فَسَلَّمَ عَلَيْهِ فَلَمْ يَرُدَّ عَلَيْهِ .
It was narrated that Ibn 'Umar said: "A man passed by the Prophet while he was urinating and greeted him with the Salam, and he did not return the greeting."
Reference : Sunan Ibn Majah 353In-book reference : Book 1, Hadith 87English translation : Vol. 1, Book 1, Hadith 353