It wasnarrated that 'Umair bin Anas bin Malik said:
"My paternalunclesamong the Ansar who were among the Companions of the MessengerofAllah (ﷺ) 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 (ﷺ) that they had seen thenew crescent the night before. The Messenger of Allah (ﷺ) commandedthem to break their fast and to go out to offer the 'Eid prayer thefollowing morning.'"
English reference: Vol. 1, Book 7, Hadith 1653
Arabic reference: Book 7, Hadith 1722