Regarding Surat Al-Baqarah Jami` at-Tirmidhi 2971
Arabic hadith text
حَدَّثَنَا ابْنُ أَبِي عُمَرَ، حَدَّثَنَا سُفْيَانُ، عَنْ مُجَالِدٍ، عَنِ الشَّعْبِيِّ، عَنْ عَدِيِّ بْنِ حَاتِمٍ، قَالَ سَأَلْتُ رَسُولَ اللَّهِ صلى الله عليه وسلم عَنِ الصَّوْمِ فَقَالَ : ( حَتََّى يَتَبَيَّنَ لَكُمُ الْخَيْطُ الأَبْيَضُ مِنَ الْخَيْطِ الأَسْوَدِ ) قَالَ فَأَخَذْتُ عِقَالَيْنِ أَحَدُهُمَا أَبْيَضُ وَالآخَرُ أَسْوَدُ فَجَعَلْتُ أَنْظُرُ إِلَيْهِمَا فَقَالَ لِي رَسُولُ اللَّهِ صلى الله عليه وسلم شَيْئًا لَمْ يَحْفَظْهُ سُفْيَانُ قَالَ " إِنَّمَا هُوَ اللَّيْلُ وَالنَّهَارُ " . قَالَ أَبُو عِيسَى هَذَا حَدِيثٌ حَسَنٌ صَحِيحٌ
Translation
Narrated 'Adi bin Hatim
"I asked the Messenger of Allah (ﷺ) about the fast, he said: 'Until the white (light) thread of dawn appears distinct to you from the black thread (of night)'" - he said: "So I took two ropes, one white and the other black to look at them. So the Messenger of Allah (ﷺ) said to me" - it was something that Sufyan (a sub narrator) did not remember - so he said: "It is only the night and the day."