The Messenger of Allah ﷺ said, "When you perform ablution, snuff water into your nose and blow it out, and when you clean yourself with stones, use an odd number."
قال رسول الله ﷺ: إذا توضأت فانتير، وإذا استجمرت فأوتر.
Narrated by Tirmidhi (27), Nasai (89), and Ibn Majah (406), all of them from the hadith of Mansur, from Hilal bin Yasaf, from Salama bin Qays, with this wording. Its isnad is sahih, and Ibn Hibban (1436) also graded it sahih.Mansur is Ibn al-Mutamir bin Abdullah Sahmi, Abu Attab (with a heavy tha followed by a ba) Kufi. Abu Hatim said, "Trustworthy." Ajli said, "A trustworthy Kufan, firmly established in hadith, he was the most firmly established of the people of Kufa. It was as if his hadith were an arrow that no one disputed. He was devoted in worship, a righteous man. He was compelled to serve as judge for two months. He had a slight Shia leaning but was not extreme in it." He is among the narrators found in the six major collections.Tirmidhi said, "The hadith of Salama bin Qays is a hasan sahih hadith."His saying "fantathar" means to bring water into the nose and then expel it so that whatever is inside comes out. And "the nathrah" is the nasal cavity.On this subject there is also the hadith of Abdullah bin Zayd bin Asim describing the manner of the Prophet's ﷺ wudu, and the hadith of Asim bin Luqayt bin Sabirah, in the chapter on running the fingers through the beard and between the fingers and toes during wudu.