The Prophet ﷺ said, "Whoever performs ablution should expel water from his nose, and whoever cleans himself with stones should use an odd number."
حدثنا عبد الرحمن حدثنا مالك عن الزهري عن أبي إدريس
أن النبي ﷺ قال من توضأ فلينثر ومن استجمر فليوتر
Its chain of transmission is sahih. Abu Idris is Khawlani, whose name was Aidullah bin Abdullah. He was reliable and authoritative, one of the senior Tabiin. Makhul said, "I have not seen anyone more knowledgeable than him." Bukhari gave his biography in al-Kabir 83/1/4, as did Ibn Abu Hatim in al-Jarh wal-Tadil 37/2/3-38, Ibn Saad in al-Tabaqat 157/2/7-158, al-Hafiz in al-Isabah 5:257-258, and Dhahabi in Tadhkirat al-Huffaz 1:53-54 and in Tarikh Islam 3:215-216.The hadith appears in Muwatta, p. 19. Muslim related it, 1:83, from Yahya bin Yahya, from Malik, with this chain. Bukhari related it, 1:229, and Muslim, 1:84, both through the route of Yunus from Zuhri.As for his saying "falyanthur," it is with the tha (the triple-dotted letter) either vowelled with damma or kasra, following the patterns of "qatala" and "daraba." This is what is established in the manuscripts marked H and M, and in a copy noted in the margin of K. In a copy noted in the margin of M it reads "falyantathir." In K it reads "falyastanthir," which agrees with what is found in Muwatta and the Sahihayn. The meaning in all these variants is close.As for "man istajmara" (whoever uses istijmar), Ibn Athir said, "Istijmar means wiping oneself with jimar, which are small stones. From this the pebbles of Hajj (jimar) are named, referring to the small stones that are thrown."As for "falyuwtir," Ibn Athir said, "That is, make the stones you cleanse yourself with an odd number, either one, or three, or five." I say, this is the linguistic meaning of "itar" (making odd). But regarding istijmar specifically, there is an established prohibition against using istijmar with fewer than three stones. See al-Muntaqa, 151, 152. So making it odd here means using three, or any odd number greater than that.