Tafsir of Fatir 35:5

O mankind, indeed the promise of Allah—to which reference is made by His, the Glorified, saying: "And to Allah return the matters," meaning the Resurrection and the recompense—is true, established, and inevitable, without contradiction.

"So let not the worldly life delude you," meaning do not let the enjoyment of its commodities divert you, nor let the preoccupation with its adornments distract you from attaining what will benefit you on the day the appointment arrives. The intended meaning is to forbid them from being deceived by it, even if the prohibition is directed at it in form, similar to the words of the Almighty: "And let not the opposition of the people lead you," and your saying: "Let me not see you here."

"And let not the Deceiver deceive you regarding Allah," for He, the Exalted and Majestic, is Pardoning, Generous, Kind, and Merciful.

"The Deceiver" (Al-Gharur): meaning the one who is excessive in deception. It is—according to what has been narrated from Ibn Abbas, Al-Hasan, and Mujahid—Satan; thus, the definite article indicates a specific entity. It is also permissible to generalize it, meaning: let not anyone whose nature is to be excessive in deception deceive you by promising you forgiveness while you persist in disobedience, saying: "Indeed, Allah forgives all sins." For even if that is possible, engaging in sins with such an expectation is akin to consuming poison while relying on the natural constitution to repel it. The prohibition is repeated for emphasis and because the two "deceptions" differ in their nature.

Abu Haywah and Abu al-Samal read "Al-Ghurur" with a damma (u), considering it an infinitive of "gharra, yaghurru" (to deceive), although it is rare for transitive verbs, or it may be the plural of "gharin" (deceiver), similar to "qu'ud" and "sujud" as both infinitives and plurals. In the case of it being an infinitive, the attribution is metaphorical.