نَّحْنُ نَقُصُّ عَلَيْكَ نَبَأَهُم بِٱلْحَقِّ ۚ إِنَّهُمْ فِتْيَةٌ ءَامَنُوا بِرَبِّهِمْ وَزِدْنَٰهُمْ هُدًى

‘Why do they not produce clear evidence?’ This question indicates that after embracing the new faith, there were prolonged discussions between these young men and the leaders of their community. But the statements made by these leaders in the course of discussions did not contain any convincing arguments in favour of polytheism (shirk). Therefore, they (the Men of the Cave) found it impossible to give up a faith whose merits stood proved for the sake of a belief which had no such advantage. On being opposed as above, had they given importance to the ‘greatness’ of the leaders of their community, they would have fallen a prey to hesitancy and doubt. But, when they gave more weight to sound reasoning and convincing arguments, it enhanced their faith. For, in respect of reasoning and arguments, these ‘great men’ appeared small to them. In spite of their outward greatness, they were found to be standing on false grounds and not on the grounds of truth.

— Source: Tazkirul Quran (Maulana Wahiduddin Khan) via Quran.com (18:13)