Musnad Ahmad 28:587

Qutaybah ibn Sa'id narrated to us, Ibn Lahi'ah narrated to us, from Huyayy ibn 'Abd Allah, from Abu 'Abd al-Rahman al-Hubuli, from 'Abd Allah ibn 'Amr ibn al-'As, that the Prophet, peace and blessings of Allah be upon him, passed by Sa'd while he was performing ablution (wudu), and he said: "What is this extravagance, O Sa'd?" He said: "Is there extravagance in ablution?" He said: "Yes, even if you were on a flowing river."