﴿ فَوَسْوَسَ لَهُمَا ٱلشَّيْطَٰنُ لِيُبْدِىَ لَهُمَا مَا وُۥرِىَ عَنْهُمَا مِن سَوْءَٰتِهِمَا وَقَالَ مَا نَهَىٰكُمَا رَبُّكُمَا عَنْ هَٰذِهِ ٱلشَّجَرَةِ إِلَّآ أَن تَكُونَا مَلَكَيْنِ أَوْ تَكُونَا مِنَ ٱلْخَٰلِدِينَ ﴾

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

Please check ayah 7:21 for complete tafsir.