that while he was in the company of `Umar, `Ammar said to `Umar, "We were in a detachment and became Junub and I blew the dust off my hands (performed the rolling over the earth and prayed.)"
Sahih al-Bukhari Book 7, Hadith 7
← Previous Hadith (on the authority of his father who said) `Ammar said so (the above Statement). And Shu`ba stroked lightly the earth with his hands and brought them close to his mouth (blew off the dust) and passed them over his face and then the backs of his hands. `Ammar said, "Ablution (meaning Tayammum here) is sufficient for a Muslim if water is not available."

Sahih al-Bukhari Book 7, Hadith 6 Next Hadith → `Ammar said to `Umar "I rolled myself in the dust and came to the Prophet (ﷺ) who said, 'Passing dusted hands over the face and the backs of the hands is sufficient for you.' "

Sahih al-Bukhari Book 7, Hadith 8