The Prophet ﷺ said, "Disputing about the Quran is disbelief."
حدثنا أحمد بن حنبل حدثنا يزيد يعني ابن هارون أخبرنا محمد بن عمرو عن أبي سلمة
عن النبي ﷺ قال المراء في القرآن كفر
No references are available.
[Its chain of transmission is hasan] It is found in Musnad Ahmad: 2/503. Ibn Hibban graded it sahih, h: 73, as did Hakim: 2/223, and Dhahabi agreed with him.