وَمَنْ يَعْشُ عَنْ ذِكْرِ الرَّحْمَنِ نُقَيِّضْ لَهُ شَيْطَانًا فَهُوَ لَهُ قَرِينٌ ﴿۳۶﴾ وَإِنَّهُمْ لَيَصُدُّونَهُمْ عَنِ السَّبِيلِ وَيَحْسَبُونَ أَنَّهُمْ مُهْتَدُونَ ﴿۳۷﴾ حَتَّى إِذَا جَاءَنَا قَالَ يَا لَيْتَ بَيْنِي وَبَيْنَكَ بُعْدَ الْمَشْرِقَيْنِ فَبِئْسَ الْقَرِينُ ﴿۳۸﴾

﴾36﴿ Wa mai ya'shu 'an zikrir Rahmaani nuqaiyid lahoo Shaitaanan fahuwa lahoo qareen
﴾37﴿ Wa innahum la yasuddoo nahum 'anis sabeeli wa yahsaboona annahum muhtadoon
﴾38﴿ Hattaaa izaa jaaa'anaa qaala yaa laita bainee wa bainaka bu'dal mashriqaini fabi'sal qareen

﴾36﴿ And whoever turns away, even slightly, from the remembrance of the Most Merciful, We appoint for him a devil, who then becomes his companion
﴾37﴿ And indeed, they (the devils) surely hinder them from the right path, while they think that they are rightly guided
﴾38﴿ Until, when he comes to Us, he will say, Oh, would that there were between me and you the distance of the east and the west, So what a wretched companion you are

[36] From this verse up to verse 67 begins the second section, which contains rebuke and warning for those who turn away from the Qur'an.
It also includes consolation for the Messenger of Allah (May Allah bless him and give him peace), affirmation of the truth of the Qur'an, a general transmitted (naqlī) proof, a detailed transmitted proof from Mūsā (peace be upon him), further rebuke of the deniers, and a detailed transmitted proof from ʿĪsā (peace be upon him).
In verse 36, there is a rebuke for turning away from the Qur'an, which arises due to love of the worldly life, whose lowliness was mentioned in the previous verse.
The phrase (وَمَنْ يَعْشُ) comes from ʿashyā; aʿshā refers to someone with weak vision—who cannot see well at night but can during the day. If someone with normal vision purposely blinds himself, the verb ʿashiya yaʿshā is used for him.
Here, the reading with a ḍammah (u) on the shīn is more common, implying the first meaning: someone with weak sight.
There is a subtle point here: turning away even slightly from the Qur'an leads to punishment—so if someone turns away completely, then he is even more certainly doomed and destroyed.
The phrase (فَهُوَ لَهُ قَرِينٌ) means that this companion (Shayṭān) never leaves him.
He makes false beliefs, actions, morals, and dealings appear good to him; prevents him from lawful things and obedience; and beautifies for him what is unlawful and sinful.
[37] The phrase (وَيَحْسَبُونَ أَنَّهُمْ مُهْتَدُونَ)—“and they think they are rightly guided”—indicates that misguidance is of two types:
1. The first type is when a person commits a sin knowing it is a sin but does so out of negligence or carelessness. This is the level of fisq (open sinfulness).
2. The second type is when the person sees the sin as a good deed and believes there is benefit in it. This is the level of bidʿah (innovation), whether in belief or action. This is far more dangerous because the person does not repent from it—he considers his bad deed to be good.
Here, the second type is intended.
This also implies that the distinction between good and evil can only be made through the Qur’an. And since this person has turned away from it, he ends up calling bad actions good.
[38] This verse contains a warning about the Hereafter. The phrase (بُعْدَ الْمَشْرِقَيْنِ) means: “I wish I had been as far from you as the two Easts are from one another,”
which can be interpreted as the distance between East and West, or as the distance between the sunrise points of winter and summer.