Sunan Abi Dawud 2339
Narrated Rib'i b. Hirash:
On the authority of a man from the Companions of the Prophet (ﷺ): People differed among themselves on the last day of Ramadan (about the appearance of the moon of Shawwal). Then two bedouins came and witnessed before the Prophet (ﷺ) swearing by Allah that they had sighted moon the previous evening. So the Messenger of Allah (ﷺ) commanded the people to break the fast. The narrator Khalaf has added in his version: "and that they should proceed to the place of prayer (for 'Id)".
حَدَّثَنَا مُسَدَّدٌ، وَخَلَفُ بْنُ هِشَامٍ الْمُقْرِئُ، قَالاَ حَدَّثَنَا أَبُو عَوَانَةَ، عَنْ مَنْصُورٍ، عَنْ رِبْعِيِّ بْنِ حِرَاشٍ، عَنْ رَجُلٍ، مِنْ أَصْحَابِ النَّبِيِّ صلى الله عليه وسلم قَالَ اخْتَلَفَ النَّاسُ فِي آخِرِ يَوْمٍ مِنْ رَمَضَانَ فَقَدِمَ أَعْرَابِيَّانِ فَشَهِدَا عِنْدَ رَسُولِ اللَّهِ صلى الله عليه وسلم بِاللَّهِ لأَهَلاَّ الْهِلاَلَ أَمْسِ عَشِيَّةً فَأَمَرَ رَسُولُ اللَّهِ صلى الله عليه وسلم النَّاسَ أَنْ يُفْطِرُوا زَادَ خَلَفٌ فِي حَدِيثِهِ وَأَنْ يَغْدُوا إِلَى مُصَلاَّهُمْ ‏.‏