Sahih al-Bukhari 4510
صحيح البخاري#4510SahihNarrated `Adi bin Hatim:I said, "O Allah's Messenger (ﷺ)! What is the meaning of the white thread distinct from the black thread? Are these two threads?" He said, "You are not intelligent if you watch the two threads." He then added, "No, it is the darkness of the night and the whiteness of the day
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: 65:37