The Messenger of Allah ﷺ said, "When you perform ablution, blow water out of your nose, and when you clean yourself with stones, use an odd number."
حدثنا عبد الرحمن عن سفيان عن منصور عن هلال بن يساف
قال رسول الله ﷺ إذا توضأت فانتثر وإذا استجمرت فأوتر
Its isnad is sahih. Its narrators are trustworthy and well-known. The hadith was reported by Tirmidhi 1/40, no. 27, in the chapter on purification, rinsing the mouth and sniffing water into the nose, and he said, hasan sahih. Also Nasai 1/67, no. 88, Ibn Majah 1/142, no. 406, and Tabarani in al-Kabir 7/37, no. 6306.