Musnad Ahmad 28:433

Muhammad ibn Ja'far narrated to us, Shu'bah narrated to us, from Abu Bishr, from a man from the people of Makkah, from Abdullah ibn Amr, from the Prophet, peace and blessings of Allah be upon him, that he saw some people who performed ablution but did not complete the ablution. He said: "Woe to the heels from the Fire."