Sunan an-Nasa'i 89

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 89

In-book

Book 1, Hadith 89