(وَلَا تُعْجِبْكَ أَمْوَالُهُمْ وَأَوْلَادُهُمْ ۚ إِنَّمَا يُرِيدُ اللَّهُ أَن يُعَذِّبَهُم بِهَا فِي الدُّنْيَا…) (And let not their wealth and their children impress you. Allah only intends to punish them through these in this world,): One might say: ‘This verse has been mentioned almost verbatim in a previous verse of this Surah, so why this repetition?’ We say: Yes, it has been mentioned before, but each has its own meaning. The first verse is:

  فَلا تُعْجِبْكَ أَمْوَالُهُمْ وَلا أَوْلادُهُمْ إِنَّمَا يُرِيدُ اللَّهُ لِيُعَذِّبَهُمْ بِهَا فِي الْحَيَاةِ الدُّنْيَا وَتَزْهَقَ أَنْفُسُهُمْ وَهُمْ كَافِرُونَ 

(So, do not let their wealth or their children impress you; Allah only intends to punish them with these in the worldly life and that their souls should depart [at death] while they are disbelievers) (At-Tawbah:55)

As for the verse here:

وَلَا تُعْجِبْكَ أَمْوَالُهُمْ وَأَوْلَادُهُمْ ۚ إِنَّمَا يُرِيدُ اللَّهُ أَن يُعَذِّبَهُم بِهَا فِي الدُّنْيَا وَتَزْهَقَ أَنفُسُهُمْ وَهُمْ كَافِرُونَ (And let not their wealth and their children impress you. Allah only intends to punish them through them in this world and that their souls should depart [at death] while they are disbelievers.)

The first difference we find is in the beginning of the two verses.

‘So’ is used in the first verse. whereas ‘And’ is used in the second one. (So) in the first verse, indicating sequence and connection. Thus, the verse is a consequence of the preceding verses, expressing the statement of Allah (swt):

  وَمَا مَنَعَهُمْ أَن تُقْبَلَ مِنْهُمْ نَفَقَاتُهُمْ إِلَّا أَنَّهُمْ كَفَرُوا بِاللَّهِ وَبِرَسُولِهِ وَلَا يَأْتُونَ الصَّلَاةَ إِلَّا وَهُمْ كُسَالَىٰ وَلَا يُنفِقُونَ إِلَّا وَهُمْ كَارِهُونَ 

(And nothing has prevented their contributions from being accepted from them except that they disbelieved in Allah and His Messenger and that they come not to prayer except while they are lazy and that they do not spend except while they are unwilling) (At-Tawbah:54)

It’s as if these are the specifications of their disbelief. They pray only as an act of hypocrisy and spend money in the cause of Allah only under compulsion. To them, the joy in wealth lies in spending it in whatever way they wish. Whereas, when a believer spends his money in charity or pays Zakat, he does so believing that Allah (swt) will reward him manifold in this world and the Hereafter. He feels joy in doing so because he has worked for the Hereafter. As for the hypocrite who hides disbelief in his heart, he does not believe in the Hereafter and does not recognize the blessings in sustenance. It’s as if he has spent his money without gaining anything in return, so he becomes reluctant. In his view, the matter represents a loss of wealth. In fact, if a person spends while being unwilling, he will feel a sense of constriction and fatigue for why would he spend while he does not believe in the Hereafter or in any reward?! Allah (swt) wants to pay our attention that the sustenance for such people is a cause of their misery and humiliation in this world. He makes them accumulate wealth through effort and toil, only to spend it without any reward. One of them might go to war with the Messenger of Allah (saws) hypocritically, spending on mounts and weapons without receiving any reward. Or Allah (swt) may grant him children, who become a source of hardship for him. So, beware, Oh believer, of being impressed by such wealth.

…وَتَزْهَقَ أَنفُسُهُمْ وَهُمْ كَافِرُونَ…  (and that their souls should depart [at death] while they are disbelievers.): Because, fundamentally, they concealed disbelief while outwardly showing faith in Allah (swt).