Sahih Muslim 6690
صحيح مسلم#6690SahihAbu Dharr reported:Allah's Apostle (ﷺ) said to me: Don't consider anything insignificant out of good things even if it is that you meet your brother with a cheerful countenance
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: 45:187