Musnad Ahmad 30:3329

Hajjaj narrated to us, Shu'bah narrated to us, from Muhammad ibn Ziyad, who said: I heard Abu Hurairah saying—and he used to pass by us while the people were performing ablution from the water container—: "Perform the ablution thoroughly, for Abu al-Qasim (peace and blessings of Allah be upon him) said: 'Woe to the heels from the Fire.'"