Mishkat al-Masabih #489

‘Ammar said that a man came to ‘Umar b. al-Khatt&b, telling that he was affected by seminal defilement and could get no water. ‘Ammar then said to ‘Umar: Do you not remember that you and I were on a journey and you did not pray, but I rolled myself on the ground, then prayed? I mentioned that afterwards to the Prophet, and he said,“It would have been enough for you to do thus”—and the Prophet struck the ground with the palms of his hands, blew into them, then wiped his face and the palms of his hands with them. Bukhari transmitted it, and Muslim has something similar, in which he said, “It is enough for you to strike the ground with your hands, then blow, then wipe your face and the palms of your hands with them.”