Ibn Abd al-Rahman bin Abza narrates from his father (may Allah be pleased with him) that he said: I was present with Sayyiduna Umar bin al-Khattab (may Allah be pleased with him) when Sayyiduna Ammar bin Yasir (may Allah be pleased with him) said to him: Do you remember when we were on a military expedition and we became junub, and I rolled about in the dust? Then we came to the Prophet (peace and blessings be upon him) and mentioned this to him (peace and blessings be upon him), and he (peace and blessings be upon him) said: "It would have sufficed you to do like this," and he described the method of tayammum.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الطهارة / 1035