Narrated Ibn Mas'ud:
"The moon was cleft asunder during the time of the Messenger of Allah (ﷺ), so the Prophet (ﷺ) said to us: 'Bear witness.'" (ES)
English reference (ES): Vol. 5, Book 44, Hadith 3287 (ES)
Arabic reference (ES): Book 47, Hadith 3598 (ES)