When God created Adam and Eve, he put them in the Garden of Eden and told them they could eat from any tree they wanted, except from the tree of the knowledge of good and evil. The day they ate of it, they would surely die.
And, you know how the story went: Eve was tempted by the serpent, ate the fruit, gave some to Adam, and because they sinned, they were separated from God, kicked out of paradise, death entered the picture, all creation was sent into upheaval, and everyone born of the seed of Adam, that's us, are under the same curse, born into sin and fallen from grace. Way to go, Adam.
But wait a second: If God is all-knowing, and he knew that eating the fruit would result in the fall of mankind, why'd he even put the tree there in there in the first place? Isn't this his fault? Well you know, Adam tried blaming God, too. "The woman you put here with me gave me some of the fruit and I ate it!" Guess how that went for him?
In Psalm 119, David said, "Oh, how I love your law! It is my meditation all the day." In other words, there is great joy when we obey God. Adam and Eve lived in perfection, and God showed His goodness all the more by giving them a command to obey that they would experience the greatest joy imaginable, needing nothing else but God.
Then the devil came along and convinced them that God and all his blessings were not enough. God is selfish and is keeping something from you, he said. So they ate the fruit, believing they needed something other than God to be satisfied.
Such is the case with our sin, too. We are all willing participants in Adam's sin. But God so loved us, He sent His Son Jesus to destroy the work of the devil. All who believe in Jesus have their sins forgiven and will be restored to eternal paradise with God when we understand the text.