Adam and Eve had a wonderful life in Eden. They had the freedom to do whatever they wanted except eat of the fruit of one particular tree.
And the Lord God commanded the man, "You are free to eat from any tree in the garden; but you must not eat from the tree of the knowledge of good and evil, for when you eat of it you will surely die." (Genesis 2:16-17)
Given that they had the run of all of Eden, Adam and Eve would surely have been inclined to obey God, but they hadn't reckoned on the deviousness of one particular creature in Eden, the serpent.
Now the serpent was more crafty than any of the wild animals the LORD God had made. He said to the woman, "Did God really say, 'You must not eat from any tree in the garden'?"
The woman said to the serpent, "We may eat fruit from the trees in the garden, but God did say, 'You must not eat fruit from the tree that is in the middle of the garden, and you must not touch it, or you will die.' "
"You will not surely die," the serpent said to the woman. "For God knows that when you eat of it your eyes will be opened, and you will be like God, knowing good and evil."
When the woman saw that the fruit of the tree was good for food and pleasing to the eye, and also desirable for gaining wisdom, she took some and ate it. She also gave some to her husband, who was with her, and he ate it. (Genesis 3:1-7)
Their disobedience immediately made the man and woman ashamed, and they tried to hide themselves from the eyes of God. God confronted them and in the first recorded instance of passing the buck, Adam put the blame for his sin on the woman, who in turn blamed the serpent.
So the LORD God said to the serpent, "Because you have done this,
cursed are you above all the livestock
and all the wild animals!
You will crawl on your belly
and you will eat dust
all the days of your life.
And I will put enmity
between you and the woman,
and between your offspring and hers;
he will crush your head,
and you will strike his heel."
Centuries later, Jesus Christ, the offspring of the woman, would crush the head of the serpent.