Hadithcore
Mishkat al-Masabih, 236

Abu Huraira reported God’s messenger as saying, “Disputation about the Qur’an is infidelity.” Ahmad and Abu Dawud transmitted it.

وَعَنْ أَبِي هُرَيْرَةَ رَضِيَ اللَّهُ عَنْهُ قَالَ: قَالَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ: «الْمِرَاءُ فِي الْقُرْآنِ كُفْرٌ» . رَوَاهُ أَحْمَدُ وَأَبُو دَاوُد

References1 variant
In-Book Reference
Book 2, Hadith 33