The Book of Purification
2/8. Chapter:
Odd numbers when rinsing the nose and cleaning oneself with pebbles (istijmar)
Sahih Muslim
حَدَّثَنِي مُحَمَّدُ بْنُ رَافِعٍ، حَدَّثَنَا عَبْدُ الرَّزَّاقِ بْنُ هَمَّامٍ، أَخْبَرَنَا مَعْمَرٌ، عَنْ هَمَّامِ بْنِ مُنَبِّهٍ، قَالَ هَذَا مَا حَدَّثَنَا أَبُو هُرَيْرَةَ، عَنْ مُحَمَّدٍ، رَسُولِ اللَّهِ صلى الله عليه وسلم فَذَكَرَ أَحَادِيثَ مِنْهَا وَقَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم " إِذَا تَوَضَّأَ أَحَدُكُمْ فَلْيَسْتَنْشِقْ بِمَنْخِرَيْهِ مِنَ الْمَاءِ ثُمَّ لْيَنْتَثِرْ " .
Hammam b. Munabbih reported: This is what Abu Huraira transmitted to us from Muhammad, the Messenger of Allah (ﷺ), and he mentioned a number of a hadith, of which this is one: that the Messenger of Allah (ﷺ) said: When anyone amongst you (performs ablution) he must snuff his nostrils with water and then clean them.
Reference : Sahih Muslim 237bIn-book reference : Book 2, Hadith 28USC-MSA web (English) reference : Book 2, Hadith 459