إِنْ يَشَأْ يُذْهِبْكُمْ وَيَأْتِ بِخَلْقٍ جَدِيدٍ ﴿۱۶﴾ وَمَا ذَلِكَ عَلَى اللَّهِ بِعَزِيزٍ ﴿۱۷﴾ وَلَا تَزِرُ وَازِرَةٌ وِزْرَ أُخْرَى وَإِنْ تَدْعُ مُثْقَلَةٌ إِلَى حِمْلِهَا لَا يُحْمَلْ مِنْهُ شَيْءٌ وَلَوْ كَانَ ذَا قُرْبَى إِنَّمَا تُنْذِرُ الَّذِينَ يَخْشَوْنَ رَبَّهُمْ بِالْغَيْبِ وَأَقَامُوا الصَّلَاةَ وَمَنْ تَزَكَّى فَإِنَّمَا يَتَزَكَّى لِنَفْسِهِ وَإِلَى اللَّهِ الْمَصِيرُ ﴿۱۸﴾ وَمَا يَسْتَوِي الْأَعْمَى وَالْبَصِيرُ ﴿۱۹﴾ وَلَا الظُّلُمَاتُ وَلَا النُّورُ ﴿۲۰﴾ وَلَا الظِّلُّ وَلَا الْحَرُورُ ﴿۲۱﴾

﴾16﴿ Iny yasha' yuzhibkum wa ya'ti bikhalqin jadeed
﴾17﴿ Wa maa zaalika 'alal laahi bi'azeez
﴾18﴿ Wa laa taziru waaziratun wizra ukhraa; wa in tad'u musqalatun ilaa himlihaa laa yuhmal minhu shai'unw wa law kaana zaa qurbaa; innamaa tunzirul lazeena yakhshawna Rabbahum bilghaibi wa aqaamus Salaah; wa man tazakkaa fa innamaa yatazakkaa linafsih; wa ilal laahil maseer
﴾19﴿ Wa maa yastawil a'maa wal baseer
﴾20﴿ Wa laz zulumaatu wa lan noor
﴾21﴿ Wa laz zillu wa lal haroor

﴾16﴿ If He wills, He can destroy you and bring forth a new creation
﴾17﴿ And this is not difficult for Allah Almighty
﴾18﴿ And no bearer of burdens will bear the burden of another. And if a heavily burdened soul calls for its load to be carried, nothing of it will be lifted, even if it be a close relative. Your warning only benefits those who fear their Lord in the unseen and establish prayer. And whoever purifies himself does so only for the benefit of his own soul. And to Allah alone is the final return
﴾19﴿ And the blind and the seeing are not equal
﴾20﴿ And neither darkness nor light
﴾21﴿ And neither shade nor heat

[16,17] Both of these are related to the previous proof—meaning they describe His complete control and absolute richness.
[18] After presenting the reasons for monotheism and refuting polytheism, there is a warning: just as the false gods of the polytheists cannot fulfill their needs in this world, they also cannot bear their sins in the Hereafter.
Those who taught them polytheism also cannot lift their burden.
"وَإِنْ تَدْعُ" implies that even with pleading and supplication, no one can bear the burden of others.
"إِنَّمَا تُنْذِرُ" is a consolation to the Prophet (May Allah bless him and give him peace), meaning that for salvation from sin (burden), there is no other way but warning (through revelation and guidance).
Also, although the arguments have been explained in detail, they do not benefit the hostile polytheists.
Therefore, Allah consoles the Prophet (May Allah bless him and give him peace) that your warning benefits those who fear (Allah).
The outward sign of this fear is the establishment of prayer, hence the mention of "أَقَامُوا الصَّلَاةَ" (they established the prayer).
"وَمَنْ تَزَكَّى" (and whoever purifies himself) indicates the benefit of the warning.
[19,20,21] This is the reason for specifying the warning to those who fear (Allah), meaning that the warning benefits those who have fear, and it does not benefit others, because there is a great difference in their states.
These examples are to prove the difference between a monotheist (one who fears Allah) and an obstinate opponent.
The first example shows that the obstinate one is like a blind person, while the monotheist is like one who sees.
Just as there is a difference between these two in perceiving light and darkness, recognizing harmful and beneficial things, the correct and incorrect paths, and so on—likewise, there is a difference between the monotheist and the polytheist in these matters.
The second example: disbelief and polytheism and their arguments are like darkness, while monotheism, faith, and its evidences are like light.
The third example: the result and reward of monotheism and faith in this world and the Hereafter is comfort, like a shadow.
And the outcome of disbelief and polytheism in this world and the Hereafter is punishment and a harsh life, like scorching heat (harūr).