Sunan Abi Dawud 173
سنن أبي داود#173SahihAnas reported:A person came to the Messenger of Allah (ﷺ). He performed ablution and left a small part equal to the space of a nail upon his foot. The Messenger of Allah (ﷺ) said to him : Go back and perform ablution well. Abu Dawud said: This tradition is not known through Jarir b. Hazim. It was transmitted only by Ibn Wahab. Another version adds the wording : “ Go back and perform the ablution well.”
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Al-AlbaniSahih
Muhammad Muhyi Al-Din Abdul HamidSahih
Zubair Ali ZaiSahih
In-book reference: 1:173