Sunan Ibn Majah Book 1, Hadith 191
The Messenger of Allah performed ablution; so he washed his feet three times.
"I saw 'Ali performing ablution and he washed his feet up to the ankles, then he said: 'I wanted to show you how your Prophet purified himself.'"
"Ibn 'Abbas came to me and asked me about this Hadith" meaning the Hadith, that she had narrated, saying that the Messenger of Allah performed ablution and washed his feet. "Ibn 'Abbas said: 'The people are insisting on washing their feet, but I do not find anything in the Qur'an except (the injunction to) wipe them.'"