وَمَا يَسْتَوِي الاَْحْيَاء وَلَا الاَْمْوَاتُ
Not alike are the blind and the seeing. Nor are (depths of) darkness and light. Nor are the shade and the sun's heat. Nor are the living and the dead.
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;
أَوَمَن كَانَ مَيْتًا فَأَحْيَيْنَـهُ وَجَعَلْنَا لَهُ نُورًا يَمْشِي بِهِ فِى النَّاسِ كَمَن مَّثَلُهُ فِي الظُّلُمَـتِ لَيْسَ بِخَارِجٍ مِّنْهَا كَذَلِكَ
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 كَالاٌّعْمَى وَالاٌّصَمِّ وَالْبَصِيرِ وَالسَّمِيعِ هَلْ يَسْتَوِيَانِ مَثَلً
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 مَن يَشَاء
Verily, Allah makes whom He wills to hear,
means. He guides them to listen to the proof and accept it and adhere it.
وَمَا أَنتَ بِمُسْمِعٍ مَّن 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 أَنتَ إِلاَّ نَذِيرٌ