'Urwah bin Az-Zubair said: "I entered upon Mawan bin Al-Hakam and we mentioned the things for which Wudu' is done. Marwan said: 'Wudu' should be done after touching the penis.' 'Urwah said: 'I did not know that.' Marwan said: 'Busrah bint Safwan told me that she heard the Messenger of Allah (ﷺ) say: "And if any one of you touches his penis, let him do Wudu'."