Sahih al-Bukhari 4868
Sahih al-Bukhari · Book 65: Prophetic Commentary on the Qur'an (Tafseer of the Prophet (pbuh)) · "...And the moon has been cleft asunder (the people of Makkah requested Prophet Muḥammad pbuh to show them a miracle, so he showed them the splitting of the moon). And if they see a sign, they turn away..." (V.54:1,2)
Narrated Anas:
حَدَّثَنَا مُسَدَّدٌ ، حَدَّثَنَا يَحْيَى ، عَنْ شُعْبَةَ ، عَنْ قَتَادَةَ ، عَنْ أَنَسٍ ، قَالَ انْشَقَّ الْقَمَرُ فِرْقَتَيْنِ.
The moon was cleft asunder into two parts.