The event of the splitting of the moon is mentioned in both the Qur’an and Hadiths as well as in historical reports. Scholars of interpretation and comprehension alike understand that Hadiths and reports should be accepted as supplementary to the Qur’an. Consequently, both have presented these narratives in such a way that it appears the text of the Qur’an holds the primary status, and the narratives convey some of its details. Furthermore, this has been explicitly stated as well.
Syed Maududi writes:
The fact is that the incident of the splitting of the moon is established by the explicit words of the Qur’an and does not depend on the narrations of Hadith. However, the narrations provide details about it and reveal when and how it occurred. (Tafheem-ul-Qur’an 5/229)
Maulana Islahi has stated:
The question remains whether such an incident occurred during the time of the Prophet (PBUH). In my opinion, the answer is that the words of the Qur’an imply that it did occur, and this is supported by Hadiths as well. The details of the incident may vary in different Hadiths, but there is no reported disagreement on the occurrence of the incident itself. (Tadabbur-e-Qur’an 8/91-92)