Sunan Ibn Majah, Hadith 409 ⓘ
It was narrated that Abu Hurairah said: "The Messenger of Allah said: 'Whoever performs ablution, let him clean his nose, and whoever uses pebbles to clean himself after defecating, let him use an odd number.'"
حَدَّثَنَا أَبُو بَكْرِ بْنُ أَبِي شَيْبَةَ، حَدَّثَنَا زَيْدُ بْنُ الْحُبَابِ، وَدَاوُدُ بْنُ عَبْدِ اللَّهِ، قَالاَ حَدَّثَنَا مَالِكُ بْنُ أَنَسٍ، عَنِ ابْنِ شِهَابٍ، عَنْ أَبِي إِدْرِيسَ الْخَوْلاَنِيِّ، عَنْ أَبِي هُرَيْرَةَ، قَالَ قَالَ رَسُولُ اللَّهِ ـ صلى الله عليه وسلم ـ " مَنْ تَوَضَّأَ فَلْيَسْتَنْثِرْ وَمَنِ اسْتَجْمَرَ فَلْيُوتِرْ " .
also referenced under: Book 1, Hadith 443 (In-Book) & Volume 1, Book 1, Hadith 409 (DarusSalam)