Concerning Allah's statement,

أُولَـئِكَ لَمْ يَكُونُواْ مُعْجِزِينَ فِي الأَرْضِ وَمَا كَانَ لَهُم مِّن دُونِ اللّهِ مِنْ أَوْلِيَاء ...

By no means will they escape on earth, nor have they protectors besides Allah!

This means that these disbelievers are under the power of Allah and His force. They are in His grasp and are subject to His authority. He is Most Able to exact vengeance against them in this life before the coming of the Hereafter.

This is like Allah's statement,

إِنَّمَا يُؤَخِّرُهُمْ لِيَوْمٍ تَشْخَصُ فِيهِ الأَبْصَـرُ

but He gives them respite up to a Day when the eyes will stare in horror. (14:42)

In the Two Sahihs it is recorded that the Prophet said,

إِنَّ اللهَ لَيُمْلِي لِلظَّالِمِ حَتَّى إِذَا أَخَذَهُ لَمْ يُفْلِتْه

Verily Allah gives respite to the oppressor until He seizes him, then he will not be able to escape Him.

For this reason Allah says,

... يُضَاعَفُ لَهُمُ الْعَذَابُ ...

Their torment will be doubled!

This means that the torment will be doubled upon them, because Allah gave them hearing, vision and hearts, but these things did not benefit them. Rather, they were deaf from hearing the truth and blinded away from following it. This is just as Allah has mentioned concerning them when they enter into the Hellfire.

Allah says,

وَقَالُواْ لَوْ كُنَّا نَسْمَعُ أَوْ نَعْقِلُ مَا كُنَّا فِى أَصْحَـبِ السَّعِيرِ

And they will say: "Had we but listened or used our intelligence, we would not have been among the dwellers of the blazing Fire!'' (67:10)

Allah also says,

الَّذِينَ كَفَرُواْ وَصَدُّواْ عَن سَبِيلِ اللَّهِ زِدْنَـهُمْ عَذَابًا فَوْقَ الْعَذَابِ

Those who disbelieved and hinder (men) from the path of Allah, for them We will add torment to the torment. (16:88)

... مَا كَانُواْ يَسْتَطِيعُونَ السَّمْعَ وَمَا كَانُواْ يُبْصِرُونَ ﴿٢٠﴾

They could not bear to listen and they used not to see (the truth).

For this reason they will be punished for every command that they abandoned and every prohibition that they indulged in.

Then Allah continues by saying,