Hazrat Adi bin Hatim narrates that when this verse of the Holy Qur'an was revealed { حَتَّی یَتَبَیَّنَ لَکُمُ الْخَیْطُ الأَبْیَضُ مِنَ الْخَیْطِ الأَسْوَد }, I said, "O Messenger of Allah! I placed two threads under my pillow, one black thread and one white thread. I try to distinguish between night and day." The Messenger of Allah (peace and blessings be upon him) said, "Your pillow is very wide indeed; in this verse, what is meant is the darkness of the night and the whiteness of the day."