Narrated Anas:
"The people of Makkah asked the Prophet (ﷺ) for a sign, so the moon was cleft asunder in Makkah two times (meaning two parts), so the following was revealed: 'The Hour has drawn near, and the moon has been cleft asunder, up to his saying: 'Magic, Mustamir (54:1 & 2)' meaning 'Going away.'" (ES)
English reference (ES): Vol. 5, Book 44, Hadith 3286 (ES)
Arabic reference (ES): Book 47, Hadith 3597 (ES)