Sahih Bukhari
Prophetic Commentary on the Quran (Tafseer of the Prophet (PBUH))
Volume: 006 / Book Number: 060 / Hadith Number: 326
Narrated Abu Dharr:
Once I was with the Prophet in the mosque at the time of sunset. The Prophet said, "O Abu Dharr! Do you know where the sun sets?" I replied, "Allah and His Apostle know best." He said, "It goes and prostrates underneath (Allah's) Throne; and that is Allah's Statement:--
'And the sun runs on its fixed course for a term (decreed). And that is the decree of All-Mighty, the All-Knowing....' (36.38)