Sunan an-Nasa'i 67
سنن النسائي#67SahihIt was narrated from 'Abdullah bin Al-Mughaffal that the Messenger of Allah (ﷺ) commanded that dogs be killed, but he made an exception for hunting dogs and sheepdogs and said:"If a dog licks a vessel then wash it seven times, and rub it the eighth time with dust
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Abu GhuddahSahih
Al-AlbaniSahih
Zubair Ali ZaiSahih Muslim
In-book reference: 1:67