The Quran

فَوَسوَسَ لَهُمَا الشَّيطانُ لِيُبدِيَ لَهُما ما وورِيَ عَنهُما مِن سَوآتِهِما وَقالَ ما نَهاكُما رَبُّكُما عَن هٰذِهِ الشَّجَرَةِ إِلّا أَن تَكونا مَلَكَينِ أَو تَكونا مِنَ الخالِدينَ

Muhammad Asad

Thereupon Satan whispered unto the two with a view to making them conscious of their nakedness, of which [hitherto] they had been unaware;¹ and he said: "Your Sustainer has but forbidden you this tree lest you two become [as] angels, or lest you live forever."²

Lit., "so as to make manifest to them that of their nakedness which [hitherto] had been imperceptible to them": an allegory of the state of innocence in which man lived before his fall from grace - that is, before his consciousness made him aware of himself and of the possibility of choosing between alternative courses of action, with all the attending temptations towards evil and the misery which must follow a wrong choice.
Lit., "or [lest] you become of those who are enduring": thus instilling in them the desire to live forever and to become in this respect, like God. (See note 106 on 20:120.)