ذِكْرُ الْبَيَانِ بِأَنَّ الْعَرَبَ تَتَبَايَنُ لُغَاتُهَا فِي أَحْيَائِهَا
When the verse "Until the white thread of dawn appear to you distinct from its black thread" was revealed, I took a white rope and a black rope, and placed them beneath my pillow ; and then I looked at them, byt they were not clear to me. So I mentioned it to the Messenger of Allah ﷺ. He laughed and said: Your pillow is so broad and lengthy ; that is (i.e. means) night and day. The version of the narrator 'Uthman has: That is the blackness of night and whiteness of day. (Using translation from Abū Dāʾūd 2349)
لَمَّا نَزَلَتْ هَذِهِ الْآيَةُ {حَتَّى يَتَبَيَّنَ لَكُمُ الْخَيْطُ الْأَبْيَضُ} مِنَ الْخَيْطِ الْأَسْوَدِ أَخَذْتُ عِقَالًا أَبْيَضَ وَعِقَالًا أَسْوَدَ فَوَضَعْتُهَا تَحْتَ وِسَادَتِي فَنَظَرْتُ فَلَمْ أَتَبَيَّنْ فَذَكَرْتُ ذَلِكَ لِلنَّبِيِّ ﷺ فَضَحِكَ وَقَالَ «إِنَّ وِسَادَكَ إِذًا لَعَرِيضٌ طَوِيلٌ إِنَّمَا هُوَ اللَّيْلُ»