Musnad Ahmad 2:121

'Abd al-Razzaq narrated to us, Ma'mar narrated to us, from al-Zuhri, from Salim, from his father: That 'Umar ibn al-Khattab, while he was standing delivering the sermon on Friday, a man from the companions of the Prophet (may Allah bless him and grant him peace) entered. 'Umar called out to him: "What time is this?" He said: "I was busy today, so I did not return to my family until I heard the call (to prayer), and I did nothing more than perform ablution (wudu)." 'Umar said: "And ablution as well? Yet you know—and in another place: you have known—that the Messenger of Allah (may Allah bless him and grant him peace) used to command (people) to perform ghusl (full ritual washing)!"