Sahih Bukhari
Rubbing hands and feet with dust (Tayammum)
Volume: 001 / Book Number: 007 / Hadith Number: 337
Narrated 'Abdur Rahman bin Abza:
'Ammar said to 'Umar "I rolled myself in the dust and came to the Prophet who said, 'Passing dusted hands over the face and the backs of the hands is sufficient for you.' "