Genesis 3 describes how the Devil, in the form of a serpent, prompted Eve to question if God was truly good. The Devil showed Eve the forbidden fruit and pointed out how beautiful it was. Surely God is withholding something from you, something you truly need, the Enemy whispered.
Genesis 3:1 - "Has God indeed said, 'You shall not eat of every tree of the garden'?"
v. 4, 5 - "You will not surely die. For God knows that in the day you eat of it your eyes will be opened, and you will be like God, knowing good and evil."