18:9
أَمْ حَسِبْتَ أَنَّ أَصْحَـٰبَ ٱلْكَهْفِ وَٱلرَّقِيمِ كَانُوا۟ مِنْ ءَايَـٰتِنَا عَجَبًا
Or have you thought that the companions of the cave and the inscription were, among Our signs, a wonder?
The Cave
أَمْ حَسِبْتَ أَنَّ أَصْحَـٰبَ ٱلْكَهْفِ وَٱلرَّقِيمِ كَانُوا۟ مِنْ ءَايَـٰتِنَا عَجَبًا
Or have you thought that the companions of the cave and the inscription were, among Our signs, a wonder?
Nearby ayahs help place verse 18:9 in sequence and meaning.
إِنَّا جَعَلْنَا مَا عَلَى ٱلْأَرْضِ زِينَةً لَّهَا لِنَبْلُوَهُمْ أَيُّهُمْ أَحْسَنُ عَمَلًا
Indeed, We have made that which is on the earth adornment for it that We may test them [as to] which of them is best in deed.
وَإِنَّا لَجَـٰعِلُونَ مَا عَلَيْهَا صَعِيدًا جُرُزًا
And indeed, We will make that which is upon it [into] a barren ground.
إِذْ أَوَى ٱلْفِتْيَةُ إِلَى ٱلْكَهْفِ فَقَالُوا۟ رَبَّنَآ ءَاتِنَا مِن لَّدُنكَ رَحْمَةً وَهَيِّئْ لَنَا مِنْ أَمْرِنَا رَشَدًا
[Mention] when the youths retreated to the cave and said, "Our Lord, grant us from Yourself mercy and prepare for us from our affair right guidance."
فَضَرَبْنَا عَلَىٰٓ ءَاذَانِهِمْ فِى ٱلْكَهْفِ سِنِينَ عَدَدًا
So We cast [a cover of sleep] over their ears within the cave for a number of years.