Nafi’ narrates: Once, I accompanied Abdullah bin Umar (may Allah be pleased with them both) for some work to Abdullah bin Abbas (may Allah be pleased with them both). When Abdullah bin Umar (may Allah be pleased with them both) stated his purpose, during the conversation that day, he mentioned this incident: Once, a man passed by the Prophet Muhammad (peace and blessings be upon him); this was in a street. The Prophet Muhammad (peace and blessings be upon him) was coming after relieving himself or urinating. That man greeted you with salam, but you did not reply to him, until he was about to leave the street. Then the Prophet Muhammad (peace and blessings be upon him) wiped his blessed hand on the wall and wiped his blessed face, then wiped his both arms again (i.e., performed tayammum), then replied to his salam. Then the Prophet Muhammad (peace and blessings be upon him) said:“I did not reply to your salam because I was not in a state of purity (wudu).”