Chapter 65: Prophetic Commentary on the Qur'an (Tafseer of the Prophet (pbuh))
Narrated '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.''
Sahih al-Bukhari 4510