Hadith 1316
Abdullah bin Umar (may Allah be pleased with them both) narrates: The Prophet Muhammad (peace and blessings be upon him) came after relieving himself near Bahr Jamal. He encountered a man who greeted him with salam, but the Prophet (peace be upon him) did not reply to his greeting. The Prophet (peace be upon him) went to a wall, placed his blessed hand on the wall, then wiped his hands over his face and both arms (i.e., performed tayammum), and then the Prophet (peace be upon him) replied to that man's salam.