Sahih al-Bukhari 3687
صحيح البخاري#3687SahihNarrated Aslam:Ibn `Umar asked me about some matters concerning `Umar. He said, "Since Allah's Messenger (ﷺ) died. I have never seen anybody more serious, hard working and generous than `Umar bin Al-Khattab (till the end of his life)
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: 62:37