Sunan Ibn Majah Book 7, Hadith 1653

حَدَّثَنَا أَبُو بَكْرِ بْنُ أَبِي شَيْبَةَ، حَدَّثَنَا هُشَيْمٌ، عَنْ أَبِي بِشْرٍ، عَنْ أَبِي عُمَيْرِ بْنِ أَنَسِ بْنِ مَالِكٍ، قَالَ حَدَّثَنِي عُمُومَتِي، مِنَ الأَنْصَارِ مِنْ أَصْحَابِ رَسُولِ اللَّهِ ـ صلى الله عليه وسلم ـ قَالُوا: أُغْمِيَ عَلَيْنَا هِلاَلُ شَوَّالٍ. فَأَصْبَحْنَا صِيَامًا. فَجَاءَ رَكْبٌ مِنْ آخِرِ النَّهَارِ فَشَهِدُوا عِنْدَ النَّبِيِّ ـ صلى الله عليه وسلم ـ أَنَّهُمْ رَأَوُا الْهِلاَلَ بِالأَمْسِ. فَأَمَرَهُمْ رَسُولُ اللَّهِ ـ صلى الله عليه وسلم ـ أَنْ يُفْطِرُوا وَأَنْ يَخْرُجُوا إِلَى عِيدِهِمْ مِنَ الْغَدِ ‏.‏

It was narrated that ‘Umair bin Anas bin Malik said:“My paternal uncles among the Ansar who were among the Companions of the Messenger of Allah (ﷺ) told me: ‘The new crescent of Shawwal was covered with clouds, so we fasted the next day. Then some riders came at the end of the day and testified to the Prophet (ﷺ) that they had seen the new crescent the night before. The Messenger of Allah (ﷺ) commanded them to break their fast and to go out to offer the ‘Eid prayer the following morning.’”