Video from Desiring God
How Did Jesus Free Us from Satan?
"As we come to Genesis 3, all is well, it seems. Genesis 1:31 says, “God saw everything that he had made, and behold, it was very good.” God did not create anything evil. It was all very good.
Then, suddenly when chapter three opens, there is this serpent. And he is clearly evil. He is calling God’s word into question. Genesis 3:1: “Did God actually say, ‘You shall not eat of any tree in the garden’?” He is devious and deceitful and destructive. God had said in Genesis 2:17, “The day that you eat of [this tree] you shall surely die.” But the serpent says in Genesis 3:4: “You will not surely die. For God knows that when you eat of it your eyes will be opened, and you will be like God, knowing good and evil.” Therefore, Jesus says of him in John 8:44 that he is both a liar and murderer:
He was a murderer from the beginning, and has nothing to do with the truth, because there is no truth in him. When he lies, he speaks out of his own character, for he is a liar and the father of lies.
Satan, That Ancient Serpent
Who is this serpent? The fullest answer is given in Revelation 12:9:
The great dragon was thrown down, that ancient serpent, who is called the devil and Satan, the deceiver of the whole world — he was thrown down to the earth, and his angels were thrown down with him.
So the serpent in the garden is the devil (which means slanderer), and Satan (which means accuser), and the deceiver of the whole world. Jesus calls him “the evil one” (Matthew 13:19) and “the ruler of this world” (John 12:31; 14:30; 16:11). The Pharisees call him “Beelzebul, the prince of demons” (Matthew 12:24). Paul calls him “the god of this age” (2 Corinthians 4:4) and “the prince of the power of the air” (Ephesians 2:2).
That’s the one we meet in Genesis 3. He is already evil, already a deceiver, already a murderer when he appears in the garden of God. In Genesis 3:15, God speaks to the serpent and pronounces judgment on him:
“The eternal Son of God had to become man, because it was the offspring of the woman who was to crush the serpent’s head.”
I will put enmity between you and the woman, and between your offspring and her offspring; he shall bruise your head, and you shall bruise his heel.." from the article: The Fall of Satan and the Victory of Christ