نَّحْنُ نَقُصُّ عَلَيْكَ نَبَأَهُم بِٱلْحَقِّ ۚ إِنَّهُمْ فِتْيَةٌ ءَامَنُوا۟ بِرَبِّهِمْ وَزِدْنَـٰهُمْ هُدًى Qur’an Al-Kahf (18:13)Na h nu naqu ss u AAalayka nabaahum bi a l h aqqi innahum fityatun a manoo birabbihim wazidn a hum hud a n
I.e., without the many legendary embellishments which, in times past, have obscured the purport of this story or parable.
Lit., "We increased [or "advanced"] them in guidance".
Their Faith carried them higher and higher on the road to Truth. Faith is cumulative. Each step leads higher and higher, by the grace and mercy of Allah.