Allah likened the hypocrites when they bought deviation with guidance, thus acquiring utter blindness, to the example of a person who started a fire. When the fire was lit, and illumnitated the surrounding area, the person benefited from it and felt safe. Then the fire was suddenly extinguished. Therefore, total darkness covered this person, and he became unable to see anything or find his way out of it. Further, this person could not hear or speak and became so blind that even if there were light, he would not be able to see. This is why he cannot return to the state that he was in before this happened to him. Such is the case with the hypocrites who preferred misguidance over guidance, deviation over righteousness. This parable indicates that the hypocrites first believed, then disbelieved, just as Allah stated in other parts of the Qur'an.
﴿ذَهَبَ اللَّهُ بِنُورِهِمْ﴾
(Allah removed their light) means, Allah removed what benefits them, and this is the light, and He left them with what harms them, that is, the darkness and smoke. Allah said,
﴿وَتَرَكَهُمْ فِي ظُلُمَـتٍ﴾
(And left them in darkness), that is their doubts, disbelief and hypocrisy.
((So) they could not see) meaning, they are unable to find the correct path or find its direction. In addition, they are,
(deaf) and thus cannot hear the guidance,
(dumb) and cannot utter the words that might benefit them,
(and blind) in total darkness and deviation. Similarly, Allah said,
﴿فَإِنَّهَا لاَ تَعْمَى الاٌّبْصَـرُ وَلَـكِن تَعْمَى الْقُلُوبُ الَّتِى فِى الصُّدُورِ﴾
(Verily, it is not the eyes that grow blind, but it is the hearts which are in the breasts that grow blind) (22:46) and this why they cannot get back to the state of guidance that they were in, since they sold it for misguidance.
﴿أَوْ كَصَيِّبٍ مِّنَ السَّمَآءِ فِيهِ ظُلُمَـتٌ وَرَعْدٌ وَبَرْقٌ يَجْعَلُونَ أَصْـبِعَهُمْ فِى ءَاذَانِهِم مِّنَ الصَّوَعِقِ حَذَرَ الْمَوْتِ وَاللَّهُ مُحِيطٌ بِالْكـفِرِينَ - يَكَادُ الْبَرْقُ يَخْطَفُ أَبْصَـرَهُمْ كُلَّمَآ أَضَآءَ لَهُم مَّشَوْاْ فِيهِ وَإِذَآ أَظْلَمَ عَلَيْهِمْ قَامُواْ وَلَوْ شَآءَ اللَّهُ لَذَهَبَ بِسَمْعِهِمْ وَأَبْصَـرِهِمْ إِنَّ اللَّهَ عَلَى كُلِّ شَىْءٍ قَدِيرٌ ﴾
(19. Or like a rainstorm in the sky, bringing darkness, thunder, and lightning. They thrust their fingers in their ears to keep out the stunning thunderclap for fear of death. But Allah ever encompasses the disbelievers.) (20. The lightning almost snatches away their sight, whenever it flashes for them, they walk therein, and when darkness covers them, they stand still. And if Allah willed, He could have taken away their hearing and their sight. Certainly, Allah has power over all things.)