When the above verses were revealed: 'Until the white thread appears to you, distinct from the black thread,' I took two (hair) strings, one black and the other white, and kept them under my pillow and went on looking at them throughout the night but could not make anything out of it. So, the next morning I went to Messenger of Allah ﷺ and told him the whole story. He explained to me, "That verse means the darkness of the night and the whiteness of the dawn."  

لَمَّا نَزَلَتْ {حَتَّى يَتَبَيَّنَ لَكُمُ الْخَيْطُ الأَبْيَضُ مِنَ الْخَيْطِ الأَسْوَدِ} عَمَدْتُ إِلَى عِقَالٍ أَسْوَدَ وَإِلَى عِقَالٍ أَبْيَضَ فَجَعَلْتُهُمَا تَحْتَ وِسَادَتِي فَجَعَلْتُ أَنْظُرُ فِي اللَّيْلِ فَلاَ يَسْتَبِينُ لِي فَغَدَوْتُ عَلَى رَسُولِ اللَّهِ ﷺ فَذَكَرْتُ لَهُ ذَلِكَ فَقَالَ إِنَّمَا ذَلِكَ سَوَادُ اللَّيْلِ وَبَيَاضُ النَّهَارِ  

" Until the white streak of the dawn becomes distinct from the dark streak" (ii. 187) Adi b. Hatim said: Messenger of Allah, verily I keep underneath my pillow two strings, one white and the other black, by which I distinguish night from dawn. Upon this the Messenger of Allah ﷺ said: Your pillow seems to be very large. For the word khait implies the blackness of the night and the whiteness of the dawn.  

لَمَّا نَزَلَتْ { حَتَّى يَتَبَيَّنَ لَكُمُ الْخَيْطُ الأَبْيَضُ مِنَ الْخَيْطِ الأَسْوَدِ مِنَ الْفَجْرِ} قَالَ لَهُ عَدِيُّ بْنُ حَاتِمٍ يَا رَسُولَ اللَّهِ إِنِّي أَجْعَلُ تَحْتَ وِسَادَتِي عِقَالَيْنِ عِقَالاً أَبْيَضَ وَعِقَالاً أَسْوَدَ أَعْرِفُ اللَّيْلَ مِنَ النَّهَارِ فَقَالَ رَسُولُ اللَّهِ ﷺ إِنَّ وِسَادَتَكَ لَعَرِيضٌ إِنَّمَا هُوَ سَوَادُ اللَّيْلِ وَبَيَاضُ النَّهَارِ  

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»  

[Machine] "When this verse was revealed: 'until the white thread of dawn becomes distinct from the black thread [of night],' I took a black thread and a white thread and placed them under my pillow. Then I looked but I could not distinguish between them, so I mentioned that to the Messenger of Allah ﷺ and he laughed and said, 'Your pillow must be very wide and long. This refers to the night and the day.'"  

لَمَّا نَزَلَتْ هَذِهِ الْآيَةُ {حَتَّى يَتَبَيَّنَ لَكُمُ الْخَيْطُ الْأَبْيَضُ مِنَ الْخَيْطِ الْأَسْوَدِ مِنَ الْفَجْرِ} أَخَذْتُ عِقَالًا أَسْوَدَ وَعِقَالًا أَبْيَضَ فَوَضَعْتُهُمَا تَحْتَ وِسَادَتِي فَنَظَرْتُ فَلَمْ أَتَبَيَّنْ فَذَكَرْتُ ذَلِكَ لِرَسُولِ اللهِ ﷺ فَضَحِكَ وَقَالَ «إِنَّ وِسَادَكَ إِذًا لَعَرِيضٌ طَوِيلٌ إِنَّمَا هَذَا اللَّيْلُ وَالنَّهَارُ»  

[Machine] "When this verse was revealed {Eat and drink until the white thread becomes distinct to you from the black thread of dawn}, I took two headbands, one black and the other white, and put them under my pillow. I raised them at night but could not determine the white from the black. So, I mentioned this to the Messenger of Allah ﷺ, and he said, 'O son of Hatim, if that is the case, then your pillow is too wide. Indeed, what Allah meant is to eat and drink until the whiteness of day becomes distinct from the darkness of night.'"  

لَمَّا نَزَلَتْ هَذِهِ الْآيَةُ {وَكُلُوا وَاشْرَبُوا حَتَّى يَتَبَيَّنَ لَكُمُ الْخَيْطُ الْأَبْيَضُ مِنَ الْخَيْطِ الْأَسْوَدِ مِنَ الْفَجْرِ} أَخَذْتُ عِقَالَيْنِ أَحَدُهُمَا أسْوَدُ وَالْآخَرُ أَبْيَضُ فَوَضَعْتُهُمَا تَحْتَ وِسَادَتِي فَرَفَعَتْهُمَا فِي اللَّيْلِ فَلَمْ أَتَبَيَّنْ الْأَبْيَضَ مِنَ الْأَسْوَدِ فَذَكَرْتُ ذَلِكَ لِرَسُولِ اللهِ ﷺ فَقَالَ يَا ابْنَ حَاتِمٍ إِنَّ وِسَادَكَ إِذًا لَعَرِيضٌ إِنَّمَا قَالَ كُلُوا وَاشْرَبُوا حَتَّى يَتَبَيَّنَ لَكُمْ بَيَاضُ النَّهَارِ مِنْ سَوَادِ اللَّيْلِ  

[Machine] When this verse was revealed, I took two ropes, one of them black and the other white, and placed them under my pillow. I raised them in the night but I could not distinguish the white from the black. I mentioned this to the Messenger of Allah ﷺ , and he said, "O son of Hatim, if your pillow had been truly wide, you would have been able to distinguish the white from the black. Allah only meant that you should eat and drink until the whiteness of the day can be distinguished from the darkness of the night."  

لَمَّا نَزَلَتْ هَذِهِ الْآيَةُ {وَكُلُوا وَاشْرَبُوا حَتَّى يَتَبَيَّنَ لَكُمُ الْخَيْطُ الْأَبْيَضُ مِنَ الْخَيْطِ الْأَسْوَدِ مِنَ الْفَجْرِ} أَخَذْتُ عِقَالَيْنِ أَحَدُهُمَا أسْوَدُ وَالْآخَرُ أَبْيَضُ فَوَضَعْتُهُمَا تَحْتَ وِسَادَتِي فَرَفَعَتْهُمَا فِي اللَّيْلِ فَلَمْ أَتَبَيَّنْ الْأَبْيَضَ مِنَ الْأَسْوَدِ فَذَكَرْتُ ذَلِكَ لِرَسُولِ اللهِ ﷺ فَقَالَ يَا ابْنَ حَاتِمٍ إِنَّ وِسَادَكَ إِذًا لَعَرِيضٌ إِنَّمَا قَالَ كُلُوا وَاشْرَبُوا حَتَّى يَتَبَيَّنَ لَكُمْ بَيَاضُ النَّهَارِ مِنْ سَوَادِ اللَّيْلِ