The Messenger of Allah ﷺ said, "When you clean yourself with stones, use an odd number."
أخبرنا إسحق بن إبراهيم قال أنبأنا جرير عن منصور عن هلال بن يساف
عن رسول الله ﷺ قال إذا استجمرت فأوتر
No references are available.
Its isnad is sahih. Tirmidhi transmitted it in the Book of Purification, the chapter on what has been said about rinsing the mouth and sniffing water into the nose (406) and elsewhere, hadith (27), from the report of Jareer bin Abdul-Hameed, with this same wording, and Hammad bin Zayd followed him in agreement, as found in Ibn Majah. Tirmidhi said, hasan sahih. It is also found in Al-Kubra, hadith (45).