[Machine] Abu Israel passed by while he was standing in the sun, so he said, "What is wrong with him?" They said, "He made a vow not to seek shade, sit, speak to anyone, and fast." So the Prophet, ﷺ , ordered him to seek shade, sit, speak to people, and complete his fast, and he did not command him to offer expiation. This is a good and authentic hadith, and it indicates that he was not ordered to offer expiation. Al-Hassan bin Umara narrated it from Habib bin Abi Thabit from Sa'id bin Jubair from Ibn Abbas, with a similar wording. In the end, he was not commanded to offer expiation. It was also narrated from Muhammad bin Kuraib from his father from Ibn Abbas, and it includes the command to offer expiation, but Muhammad bin Kuraib is weak.  

مَرَّ بِأَبِي إِسْرَائِيلَ وَهُوَ قَائِمٌ فِي الشَّمْسِ فَقَالَ مَا لَهُ؟ فَقَالُوا نَذَرَ أَنْ لَا يَسْتَظِلَّ وَلَا يَقْعُدَ وَلَا يُكَلِّمَ أَحَدًا وَيَصُومَ فَأَمَرَهُ النَّبِيُّ صَلَّى اللهَ عَلَيْهِ وَسَلَّمَ أَنْ يَسْتَظِلَّ وَأَنْ يَقْعُدَ وَأَنْ يُكَلِّمَ النَّاسَ وَيُتِمَّ صَوْمَهُ وَلَمْ يَأْمُرْهُ بِكَفَّارَةٍ هَذَا مُرْسَلٌ جَيِّدٌ وَفِيهِ وَفِيمَا قَبْلَهُ دَلَالَةٌ عَلَى أَنَّهُ لَمْ يَأْمُرْ بِكَفَّارَةٍ وَرَوَاهُ الْحَسَنُ بْنُ عُمَارَةَ عَنْ حَبِيبِ بْنِ أَبِي ثَابِتٍ عَنْ سَعِيدِ بْنِ جُبَيْرٍ عَنِ ابْنِ عَبَّاسٍ ؓ بِمِثْلِهِ وَفِي آخِرِهِ وَلَمْ يَأْمُرْهُ بِالْكَفَّارَةِ وَرُوِيَ عَنْ مُحَمَّدِ بْنِ كُرَيْبٍ عَنْ أَبِيهِ عَنِ ابْنِ عَبَّاسٍ ؓ وَفِيهِ الْأَمْرُ بِالْكَفَّارَةِ وَمُحَمَّدُ بْنُ كُرَيْبٍ ضَعِيفٌ