Sahih al-Bukhari 3707
صحيح البخاري#3707SahihNarrated Ubaida: Ali said (to the people of 'Iraq), "Judge as you used to judge, for I hate differences (and I do my best ) till the people unite as one group, or I die as my companions have died
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Every narration in Sahih al-Bukhari is accepted as Sahih (authentic) by the established status of the book.
In-book reference: 62:57