Sahih Muslim 6172
صحيح مسلم#6172SahihAbdullah b. Mas'ud reported Allah's Messenger (ﷺ) as saying:If I were to choose a bosom friend I would have definitely chosen Abu Bakr as my bosom friend, but he is my brother and my companion and Allah, the Exalted and Gliorious. has taken your brother and companion (meaning Prophet himself) as a friend
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: 44:4