Tafsir of Fatir 35:5

{The promise of Allah is true} regarding the recompense of reward and punishment.

{So let not the worldly life delude you}—do not let it deceive you, nor let the enjoyment of it and the savoring of its benefits distract you from working for the Hereafter and seeking what is with Allah.

{And let not the Deceiver deceive you about Allah}—do not let him say to you: "Do whatever you wish, for Allah is Forgiving; He forgives every major sin and pardons every transgression." The "Deceiver" is Satan, for that is his habit. It has also been recited with a damma (al-ghurur), in which case it is an infinitive (like al-luzum and al-nuhuk) or the plural of ghar (like qa'id and qu'ud).

Allah, the Almighty and Exalted, has informed us that Satan is a manifest enemy to us. He recounted his story and what he did to our father Adam (peace be upon him), and how he committed himself to the enmity of our kind both before and after his existence. Yet, despite this, we take him as an ally and obey him in what he desires from us—that which leads to our destruction.

Therefore, He admonished us—Exalted is He—that since you know he is your enemy, and there is no enemy more deeply rooted in enmity than he, yet you treat him as one who is ignorant of his state:

{Then take him as an enemy} in your beliefs and your actions. Let there be nothing found in you except what indicates your enmity and opposition toward him, both in your secret and your public affairs.

Then, He summarized the secret of his affair and the error of those who follow him, explaining that his goal in inviting his faction and those who follow his footsteps is to lead them to the place of misery and destruction, so that they may become companions of the Blaze.

Then, He lifted the veil and peeled away the bark to sever empty hopes and false desires, basing the entire matter upon faith and action, or the abandonment of them.

{Is he to whom the evil of his deed has been made attractive so that he considers it good [like one who is guided]? For indeed, Allah sends astray whom He wills and guides whom He wills. So do not let yourself perish in sorrow over them. Indeed, Allah is Knowing of what they do.}