•Holy Quran 43:37
وَإِنَّهُمْ لَيَصُدُّونَهُمْ عَنِ السَّبِيلِ وَيَحْسَبُونَ أَنَّهُم مُّهْتَدُونَ
And verily, they (Satans / devils) hinder them from the Path (of Allah), but they think that they are guided aright!
•Holy Quran 43:38
حَتَّىٰ إِذَا جَاءَنَا قَالَ يَا لَيْتَ بَيْنِي وَبَيْنَكَ بُعْدَ الْمَشْرِقَيْنِ فَبِئْسَ الْقَرِينُ
Till, when (such a one) comes to Us, he says [to his Qarin (Satan / devil companion)] "Would that between me and you were the distance of the two easts (or the east and west)" a worst (type of) companion (indeed)!
•(And whosoever Ya`shu (turns away blindly)) means, whoever willfully ignores and turns away (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.
•(We appoint for him Shaytan to be a Qarin (a companion) to him.) This is like the Ayat:
•(And whoever contradicts and opposes the Messenger after the right path has been shown clearly to him) (4:115),
•(So when they turned away, Allah turned their hearts away) (61:5), and
•(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:
•(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.
•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.
•[Tafsir Ibn Kathir Surah as-Zukhruf: 36-38, https://abdurrahman.org/2011/12/01/whosoever-turns-away-blindly-from-the-remembrance-of-the-most-gracious-we-appoint-for-him-shaytan-to-be-a-qarin/]