Reading from the Book of Genesis 3:15
Genesis 3:15 And
I will put enmity between thee and the woman, and between thy seed and
her seed; it shall bruise thy head, and thou shalt bruise his heel.
I believe that Adam was clothed with Gods glory before he sinned. As soon as Adam and Eve sinned, they realized they were naked. We might say they lost their "covering." As long as they obeyed God, they were protected from everything the devil wanted to do to them, and ultimately, through them. Upon seeing what the devil had done, God immediately announced Satan's doom and told him how it would occur. Satan did not really understand what God was saying, nevertheless, God said it, and it had come to pass.
To "bruise the head" symbolizes a weakening of authority. God has said that the woman's Offspring (Jesus) will take away Satan's authority (which Adam gave him) and gave it first to Jesus and then to every person who will believe. Not only that Jesus died for them, but also that Satan has lost authority over them. We need to understand not only that Jesus died for us, but also that He has redeemed us!
No matter what the devil tries to do to you, he is doomed to defeat, and you are redeemed and victorious over him through Jesus Christ.