Musnad Ahmad 1060:45

Waki’ narrated to us, Quraysh ibn Hayyan narrated to us, from Abu Wasil, who said: I met Abu Ayyub al-Ansari and he shook my hand. He saw length in my fingernails, so he said: The Messenger of Allah (peace and blessings of Allah be upon him) said: "One of you asks about the news of the heaven, while he leaves his fingernails like the talons of birds, in which impurity, filth, and dirt gather." Waki’ did not say "al-Ansari" once. Someone else said: "Abu Ayyub al-‘Ataki." Abu ‘Abd al-Rahman said: My father said: "His tongue slipped," meaning Waki’, "so he said: I met Abu Ayyub al-Ansari, but it is only Abu Ayyub al-‘Ataki."