Sahih al-Bukhari 6738
صحيح البخاري#6738SahihNarrated Ibn `Abbas:The person about whom Allah's Messenger (ﷺ) said, "If I were to take a Khalil from this nation (my followers), then I would have taken him (i.e., Abu Bakr), but the Islamic Brotherhood is better (or said: good)," regarded a grandfather as the father himself (in inheritance)
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: 85:15