Fussilat 41:52

Qul araaytum in kana min AAindi Allahithumma kafartum bihi man adallu mimman huwa fee shiqaqinbaAAeed

Say, "Have you considered: if it [i.e., the Qur’ān] is from Allāh and you disbelieved in it, who would be more astray than one who is in extreme dissension?"

Say (to the disbelievers), “Tell me, if it (the Qur’ān) is from Allah, and still you reject it, then who can be more erroneous than him who is (involved) in far reaching schism?”