Maliks Muwatta Book 002, Hadith Number 003.

Section : How to do Wudu.

Yahya related to me from Ibn Shihab from Abu Idris al-Khawlani from Abu Hurayra that the Messenger of Allah, may Allah bless him and grant him peace, said, "The person doing wudu should snuff water up his nose and blow it out again."