يَوْمَ يَغْشَاهُمُ الْعَذَابُ مِن فَوْقِهِمْ وَمِن تَحْتِ أَرْجُلِهِمْ ...

On the Day when the torment (Hellfire) shall cover them from above them and from beneath their feet,

This is like the Ayah,

لَهُم مِّن جَهَنَّمَ مِهَادٌ وَمِن فَوْقِهِمْ غَوَاشٍ

Theirs will be a bed of Hell, and over them coverings (of Hell-fire). (7:41)

لَهُمْ مِّن فَوْقِهِمْ ظُلَلٌ مِّنَ النَّارِ وَمِن تَحْتِهِمْ ظُلَلٌ

They shall have coverings of Fire, above them and coverings (of Fire) beneath them. (39:16)

لَوْ يَعْلَمُ الَّذِينَ كَفَرُواْ حِينَ لاَ يَكُفُّونَ عَن وُجُوهِهِمُ النَّارَ وَلاَ عَن ظُهُورِهِمْ

If only those who disbelieved knew (the time) when they will not be able to ward off the Fire from their faces, nor from their backs. (21:39)

The Fire will cover them from all sides, which is more effective as a physical punishment.

... وَيَقُولُ ذُوقُوا مَا كُنتُمْ تَعْمَلُونَ ﴿٥٥﴾

and it will be said: "Taste what you used to do.''

This is a threat and a rebuke, which is a form of psychological punishment, as in the Ayah,

يَوْمَ يُسْحَبُونَ فِى النَّارِ عَلَى وُجُوهِهِمْ ذُوقُواْ مَسَّ سَقَرَ

إِنَّا كُلَّ شَىْءٍ خَلَقْنَـهُ بِقَدَرٍ

The Day they will be dragged on their faces into the Fire (it will be said to them): "Taste you the touch of Hell!''

Verily, We have created all things with a measurement. (54:48-49)

يَوْمَ يُدَعُّونَ إِلَى نَارِ جَهَنَّمَ دَعًّا

هَـذِهِ النَّارُ الَّتِى كُنتُم بِهَا تُكَذِّبُونَ

أَفَسِحْرٌ هَـذَا أَمْ أَنتُمْ لاَ تُبْصِرُونَ

اصْلَوْهَا فَاصْبِرُواْ أَوْ لاَ تَصْبِرُواْ سَوَآءٌ عَلَيْكُمْ إِنَّمَا تُجْزَوْنَ مَا كُنتُمْ تَعْمَلُونَ

The Day when they will be pushed down by force to the fire of Hell, with a horrible, forceful pushing. This is the Fire which you used to deny. Is this magic or do you not see!

Enter you therein (taste you therein its heat) and whether you are patient of it or impatient of it, it is all the same. You are only being requited for what you used to do. (52:13-16)