Sahih Muslim 239
صحيح مسلم#239SahihIt is narrated on the authority of Abu Sa'id Khudri that the Messenger of Allah observed:The person who believes in Allah and the Last Day never nurses a grudge against the Ansar
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Every narration in Sahih Muslim is accepted as Sahih (authentic) by the established status of the book.
In-book reference: 1:145