Tafsir Ibn Kathir -> Surah Az-Zukhruf -> The Shaytan is the Companion of the One Who turns away from Ar-Rahman

﴿وَمَن يَعْشُ﴾

(And whosoever Ya`shu (turns away blindly)) means, whoever willfully ignores and turns away

﴿عَن ذِكْرِ الرَّحْمَـنِ﴾

(from the remembrance of the Most Gracious,) Al-`Asha (the root of Ya`sh) refers to weakness of vision; what is meant here is weakness of insight.

﴿نُقَيِّضْ لَهُ شَيْطَاناً فَهُوَ لَهُ قَرِينٌ﴾

(We appoint for him Shaytan to be a Qarin (a companion) to him.) This is like the Ayat:

﴿وَمَن يُشَاقِقِ الرَّسُولَ مِن بَعْدِ مَا تَبَيَّنَ لَهُ الْهُدَى﴾

(And whoever contradicts and opposes the Messenger after the right path has been shown clearly to him) (4:115),

﴿فَلَمَّا زَاغُواْ أَزَاغَ اللَّهُ قُلُوبَهُمْ﴾

(So when they turned away, Allah turned their hearts away) (61:5), and

﴿وَقَيَّضْنَا لَهُمْ قُرَنَآءَ فَزَيَّنُواْ لَهُم مَّا بَيْنَ أَيْدِيهِمْ وَمَا خَلْفَهُمْ﴾

(And We have assigned for them intimate companions, who have made fair seeming to them, what was before them and what was behind them) (41:25). Allah says here:

﴿وَإِنَّهُمْ لَيَصُدُّونَهُمْ عَنِ السَّبِيلِ وَيَحْسَبُونَ أَنَّهُم مُّهْتَدُونَ حَتَّى إِذَا جَآءَنَا﴾

(And verily, they hinder them from the path, but they think that they are guided aright! Until, when he comes to Us,) meaning, for this person who willfully neglects true guidance, We send to him a Shaytan to lead him astray and show him the path to Hell. When he comes before Allah on the Day of Resurrection, he will complain about the Shaytan who was appointed to accompany him.

﴿قَالَ يلَيْتَ بَيْنِي وَبَيْنَكَ بُعْدَ الْمَشْرِقَيْنِ فَبِئْسَ الْقَرِينُ﴾

(he says, "Would that between me and you were the distance of the two easts -- a worst companion (indeed)!'') Some of them recited it; (حَتْى إِذَا جَاءَانَا) (Till, when they both come to Us.) referring to the companion Shaytan and the one whom he accompanies. Then Allah says:

﴿وَلَن يَنفَعَكُمُ الْيَوْمَ إِذ ظَّلَمْتُمْ أَنَّكُمْ فِى الْعَذَابِ مُشْتَرِكُونَ ﴾

(It will profit you not this Day as you did wrong, (and) that you will be sharers in the punishment.) means, `your being together in the Fire will not help you in the slightest, and you will both partake of the painful punishment.' Allah says:

﴿أَفَأَنتَ تُسْمِعُ الصُّمَّ أَوْ تَهْدِى الْعُمْىَ وَمَن كَانَ فِى ضَلَـلٍ مُّبِينٍ ﴾

Can you make the deaf to hear, or can you guide the blind or him who is in manifest error؟ means, `that is not up to you. All you have to do is convey the Message, but you do not have to guide them. Allah guides whomsoever He wills and sends astray whomsoever He wills, and He is Wise and Just in doing so.'