Not alike are the blind and the seeing (19)Nor are (depths of) darkness and light (20)Nor are the shade and the sun's heat (21)Nor are the living and the dead. Verily, Allah makes whom He wills to hear, but you cannot make hear those who are in graves (22)You are only a warner (23)Verily, We have sent you with the truth, a bearer of glad tidings and a warner. And there never was a nation but a warner had passed among them (24)And if they deny you, those before them also denied. Their Messengers came to them with clear signs, and with the Scriptures, and with the Book giving light (25)Then I took hold of those who disbelieved, and how terrible was My denial (26)

The Believer and the Disbeliever are not equal

Allah says that these antonyms are clearly not equal, the blind and the seeing are not equal, there is a difference and a huge gap between them. Darkness and light are not equal, neither are shade and the sun's heat. By the same token, the living and the dead are not equal. This is the parable Allah makes of the believers who are the living, and the disbelievers who are the dead. This is like the Ayat:

أَوَمَنْ كَانَ مَيْتًا فَأَحْيَيْنَاهُ وَجَعَلْنَا لَهُ نُورًا يَمْشِي بِهِ فِي النَّاسِ كَمَنْ مَثَلُهُ فِي الظُّلُمَاتِ لَيْسَ بِخَارِجٍ مِنْهَا ۚ 

(Is he who was dead and We gave him life and set for him a light (of belief) whereby he can walk amongst men – like him who is in the (depths of) darkness from which he can never come out?)(6:122),

مَثَلُ الْفَرِيقَيْنِ كَالْأَعْمَىٰ وَالْأَصَمِّ وَالْبَصِيرِ وَالسَّمِيعِ ۚ هَلْ يَسْتَوِيَانِ مَثَلًا ۚ 

(The parable of the two parties is as that of the blind and the deaf and the seer and the hearer. Are they equal when compared?)(11:24)

The believer sees and hears, and walks in the light upon a straight path in this world and the Hereafter, until he comes to settle in Gardens (Paradise) wherein is shade and springs. The disbeliever is blind and deaf, walking in darkness from which he cannot escape, he is lost in his misguidance in this world and the Hereafter, until he ends up in fierce hot wind and boiling water, and shadow of black smoke, neither cool nor good.

إِنَّ اللَّهَ يُسْمِعُ مَنْ يَشَاءُ ۖ 

(Verily, Allah makes whom He wills to hear,) means. He guides them to listen to the proof and accept it and adhere it.

 وَمَا أَنْتَ بِمُسْمِعٍ مَنْ فِي الْقُبُورِ

(but you cannot make hear those who are in graves.) means, 'just as the dead cannot benefit from guidance and the call to truth after they have died as disbelievers and ended up in the graves, so too you cannot help these idolators who are decreed to be doomed, and you cannot guide them.'

إِنْ أَنْتَ إِلَّا نَذِيرٌ 

(You are only a warner) means, 'all you have to do is to convey the Message and warn them, and Allah leaves astray whomsoever He wills and guides whomsoever He wills.'

إِنَّا أَرْسَلْنَاكَ بِالْحَقِّ بَشِيرًا وَنَذِيرًا ۚ 

(Verily, We have sent you with the truth, a bearer of glad tidings and a warner.) means, a bearer of glad tidings to the believers and a warner to the disbelievers.

 وَإِنْ مِنْ أُمَّةٍ إِلَّا خَلَا فِيهَا نَذِيرٌ 

(And there never was a nation but a warner had passed among them.) means, there was never any nation among the sons of Adam but Allah sent warners to them, and left them with no excuse. This is like the Ayat:

إِنَّمَا أَنْتَ مُنْذِرٌ ۖ وَلِكُلِّ قَوْمٍ هَادٍ

(You are only a warner, and to every people there is a guide)(13:7).

وَلَقَدْ بَعَثْنَا فِي كُلِّ أُمَّةٍ رَسُولًا أَنِ اعْبُدُوا اللَّهَ وَاجْتَنِبُوا الطَّاغُوتَ ۖ فَمِنْهُمْ مَنْ هَدَى اللَّهُ وَمِنْهُمْ مَنْ حَقَّتْ عَلَيْهِ الضَّلَالَةُ ۚ

(And verily, We have sent among every Ummah a Messenger (proclaiming): "Worship Allah, and avoid all false deities." Then of them were some whom Allah guided and of them were some upon whom the straying was justified)(16:36). And there are many similar Ayat.

وَإِنْ يُكَذِّبُوكَ فَقَدْ كَذَّبَ الَّذِينَ مِنْ قَبْلِهِمْ جَاءَتْهُمْ رُسُلُهُمْ بِالْبَيِّنَاتِ

(And if they deny you, those before them also denied. Their Messengers came to them with clear signs,) means, clear miracles and definitive proofs.

وَبِالزُّبُرِ

(and with the Scriptures,) means, the Books.

وَبِالْكِتَابِ الْمُنِيرِ

(and with the Book giving light.) means, clear and obvious.

ثُمَّ أَخَذْتُ الَّذِينَ كَفَرُوا ۖ 

(Then I took hold of those who disbelieved,) means, 'despite all of this, they denied the Messengers and the Message they brought, so I seized them, i.e., with My punishment.'

فَكَيْفَ كَانَ نَكِيرِ

(and how terrible was My denial!) means, 'how great and intense and terrible do you think My punishment was?' And Allah knows best.