Narrated Abu Dharr:
Once I was with the Prophet (ﷺ) in the mosque at the time of sunset. The Prophet (ﷺ) 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)
USC-MSA web (English) reference: Vol. 6, Book 60, Hadith 326
Arabic reference: Book 65, Hadith 4802