Sahih al-Bukhari 4865

Arabic

حَدَّثَنَا عَلِيٌّ، حَدَّثَنَا سُفْيَانُ، أَخْبَرَنَا ابْنُ أَبِي نَجِيحٍ، عَنْ مُجَاهِدٍ، عَنْ أَبِي مَعْمَرٍ، عَنْ عَبْدِ اللَّهِ، قَالَ انْشَقَّ الْقَمَرُ وَنَحْنُ مَعَ النَّبِيِّ صلى الله عليه وسلم فَصَارَ فِرْقَتَيْنِ، فَقَالَ لَنَا ‏ "‏ اشْهَدُوا، اشْهَدُوا ‏"‏‏.‏

English translation

Narrated `Abdullah:The moon was cleft asunder while we were in the company of the Prophet, and it became two parts. The Prophet (ﷺ) said, Witness, witness (this miracle)

Reference: Sahih al-Bukhari 4865, Book of Prophetic Commentary on the Qur'an (Tafseer of the Prophet (pbuh)). English translation by Dr. Muhammad Muhsin Khan.