(Quran: The ONLY Source)
We place shields around their minds, to prevent them from understanding it, and deafness in their ears. And when you preach your Lord, using the Quran alone,* they run away in aversion.
وَجَعَلنا عَلىٰ قُلوبِهِم أَكِنَّةً أَن يَفقَهوهُ وَفى ءاذانِهِم وَقرًا وَإِذا ذَكَرتَ رَبَّكَ فِى القُرءانِ وَحدَهُ وَلَّوا عَلىٰ أَدبٰرِهِم نُفورًا
wa ja’alnaa ‘alaa quloo bihim akinnatan any yafqahoohu wa feee aazaanihim waqraa; wa izaa zakarta Rabbaka fil Quraani wahdahoo wallaw ‘alaaa adbaarihim nufooraa
*17:46 The Arabic word “alone” refers to God in 7:70, 39:45, 40:12 & 84, and 60:4. If you add these numbers, you get 361, 19×19. But if you include 17:46, which refers to the Quran, the product is not a multiple of 19. “Alone,” therefore refers to the Quran in 17:46 (Appendix 18).