أَوْ يَأْخُذَهُمْ عَلَى تَخَوُّفٍ ...

Or that He may punish them where they fear it most!

meaning, or Allah will take from them what they most fear, which is even more frightening, because when the thing you most fear to happen does happen, this is even worse.

Hence Al-Awfi reported that Ibn Abbas said that, َوْ يَأْخُذَهُمْ عَلَى تَخَوُّفٍ (Or that He may punish them where they fear it most), means that Allah is saying:

`If I wish, I can take him after the death of his companion and after he has become frightened of that.'

This was also reported from Mujahid, Ad-Dahhak, Qatadah and others.

Then Allah says:

... فَإِنَّ رَبَّكُمْ لَرؤُوفٌ رَّحِيمٌ ﴿٤٧﴾

Indeed your Lord is full of kindness, Most Merciful.

meaning, because He does not hasten to punish, as was reported in the Two Sahihs:

لَا أَحَدَ أَصْبَرُ عَلَى أَذًى سَمِعَهُ مِنَ اللهِ، إِنَّهُمْ يَجْعَلُونَ لَهُ وَلَدًا وَهُوَ يَرْزُقُهُمْ وَيُعَافِيهِم

No one is more patient in the case of hearing offensive speech than Allah, for they attribute to Him a son, while He (alone) is giving them provision and good health.

And it is also recorded in Two Sahihs,

إِنَّ اللهَ لَيُمْلِي لِلظَّالِمِ حَتَّى إِذَا أَخَذَهُ لَمْ يُفْلِتْه

Allah will let the wrongdoer continue until, when He begins to punish him, He will never let him go.

Then the Messenger of Allah recited:

وَكَذلِكَ أَخْذُ رَبِّكَ إِذَا أَخَذَ الْقُرَى وَهِىَ ظَـلِمَةٌ إِنَّ أَخْذَهُ أَلِيمٌ شَدِيدٌ

Such is the punishment of your Lord when He seizes the (population of) towns while they are doing wrong. Indeed, His punishment is painful, (and) severe. (11:102)

And Allah says:

وَكَأَيِّن مِّن قَرْيَةٍ أَمْلَيْتُ لَهَا وَهِىَ ظَـلِمَةٌ ثُمَّ أَخَذْتُهَا وَإِلَىَّ الْمَصِيرُ

And many a township did I give respite while it was given to wrongdoing. Then I punished it. And to Me is the (final) return (of all). (22:48)