Mishkat al-Masabih #495

‘Ammar b. Yasir used to tell that when they were with God’s messenger they wiped themselves with earth for the dawn prayer, striking the palms of their hands on the earth, then wiping their faces once. They struck the palms of their hands again on the earth and wiped their arms completely up to the shoulders, and up to the armpits on the inside of their arms. Abu Dawud transmitted it.