90:12
وَمَآ أَدْرَىٰكَ مَا ٱلْعَقَبَةُ
And what can make you know what is [breaking through] the difficult pass?
The City
وَمَآ أَدْرَىٰكَ مَا ٱلْعَقَبَةُ
And what can make you know what is [breaking through] the difficult pass?
Nearby ayahs help place verse 90:12 in sequence and meaning.
وَهَدَيْنَـٰهُ ٱلنَّجْدَيْنِ
And have shown him the two ways?
فَلَا ٱقْتَحَمَ ٱلْعَقَبَةَ
But he has not broken through the difficult pass.
فَكُّ رَقَبَةٍ
It is the freeing of a slave
أَوْ إِطْعَـٰمٌ فِى يَوْمٍ ذِى مَسْغَبَةٍ
Or feeding on a day of severe hunger