Musannaf Ibn Abi Shayba 1:2048

Qabisah ibn Uqbah narrated to us, from Hammad ibn Salamah, from Ali ibn Zayd, from Salamah ibn Muhammad, from Ammar ibn Yasir, who said: The Messenger of Allah (peace and blessings of Allah be upon him) said: "The *fitrah* (natural disposition) is rinsing the mouth, sniffing water into the nose, using the *siwak* (tooth stick), trimming the mustache, plucking the armpit hair, washing the knuckles, clipping the nails, sprinkling water (on the private parts), and circumcision."