Sahih Muslim 5696
صحيح مسلم#5696SahihAbdullah reported Allah's Messenger (ﷺ) as saying:If you are three, two amongst you should not converse secretly between yourselves to the exclusion of the other (third one), unti some other people join him (and dispel his loneliness), for it may hurt his feelings
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: 39:50