The Book of Purification
1/72. Chapter:
The Command To Blow (Water From The Nose)
Sunan an-Nasai
أَخْبَرَنَا قُتَيْبَةُ، قَالَ حَدَّثَنَا حَمَّادٌ، عَنْ مَنْصُورٍ، عَنْ هِلاَلِ بْنِ يِسَافٍ، عَنْ سَلَمَةَ بْنِ قَيْسٍ، أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم قَالَ " إِذَا تَوَضَّأْتَ فَاسْتَنْثِرْ وَإِذَا اسْتَجْمَرْتَ فَأَوْتِرْ " .
It was narrated from Salamah bin Qais that the Messenger of Allah (ﷺ) said: "When you perform Wudu', sniff water in your nose and blow it out, and when you use small stones (to remove filth), then make it off (numbered)."
Reference : Sunan an-Nasa'i 89In-book reference : Book 1, Hadith 89English translation : Vol. 1, Book 1, Hadith 89