Najiyah bin Ka'b narrates: Sayyiduna Ammar (may Allah be pleased with him) said to Sayyiduna Umar (may Allah be pleased with him): Do you remember, when you and I were herding camels, I became junub (in a state of major ritual impurity), so I rolled on the ground as an animal rolls. Then I presented myself before the Noble Prophet (peace and blessings be upon him) and we mentioned this matter before him, so he (peace and blessings be upon him) said: "For you, it would have been sufficient to perform tayammum in its place."