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 wasnarrated that ‘Umair bin Anas bin Malik said: “My paternalunclesamong the Ansar who were among the Companions of the MessengerofAllah (PBUH) told me: ‘The new crescent of Shawwal was covered withclouods, so we fasted the next day. Then some riders came at the endof the day and testified to the Prophet (PBUH) that they had seen thenew crescent the night before. The Messenger of Allah (PBUH) commandedthem to break their fast and to go out to offer the ‘Eid prayer thefollowing morning.’” Translation Not Available

Book Ref: Sunan Ibn Majah Book 7 Hadith 1653
Web Ref:  Sunan Ibn Majah Vol 1 Book 7 Hadith 1653