Musannaf Ibn Abi Shayba 1:1672

Abu Bakr narrated to us, he said: Ibn ‘Ulayyah narrated to us, from Ibn Jurayj, from ‘Ata’, who said: Abu Dharr became in a state of major ritual impurity (janabah) while he was with the Prophet (ﷺ) at a distance of three [days' journey]. He came [to the Prophet] when he had finished the morning prayer and had gone out to relieve himself. He (the Prophet) turned toward him, then placed his hand in the dust and wiped his face and his palms.