The LORD GOD, you know, the one WHO created you, told the serpent in Genesis chapter 3:
13 And the LORD God said unto the woman, What is this that thou hast done? And the woman said, The serpent beguiled me, and I did eat.
Revelations 12:9
And the great dragon was cast out, that old serpent, called the Devil, and Satan,
which deceiveth the whole world: he was cast out into the earth, and his angels were cast out with him.
2 Verses both highlighted with words
beguiled and deceiveth.
There was 2 TREES mentioned, "Tree of Life and Tree of Knowledge."
The Serpent kept Eve from eating from the Tree of Life by deceiving her she could become wise as God by eating the other tree.
Why would the Serpent even care about this, or care that if Eve ate this she was disobeying God?
The serpent cared because the serpent in this story is God's opponent. And God's opponent equals to our Adversary. This is how we know this serpent is the "Adversary/Devil/Satan."
And to be specific, IT DOES NOT say this in Genesis, but it explains this from the other Books of the Bible.