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.'" (TR)
English reference (TR): Vol. 5, Book 44, Hadith 3287 (TR)
Arabic reference (TR): Book 47, Hadith 3598 (TR)