The Bible describes Satan as a thief that comes but to kill, to steal and to destroy (John 10:10). Your adversary the devil walks about like a roaring lion, seeking whom he may devour (1 Peter 5:8). We can enjoy protection from the devil through faith. “The whole world is under the sway of the wicked one [Satan],” 1 John 5:9.
The unredeemed are under Satan’s influence. For the redeemed (or children of God) we have victory over the devil through our faith in Jesus. Our faith in Jesus (our believing that Jesus is the Son of God) is what helps believers overcome Satan. Jesus was sent by God to destroy the works of the devil (1 John 3:8). The devil has no claim on us. It’s our trust in Jesus and His victory over the devil that will enable us to be victorious in overcoming all issues that may come into our lives.
Some battles with the enemy may be physical struggles, like in the case of Job. God gave Satan access to Job. Job lost his family, his wealth, and his health as a result of Satan’s attack. Job remained loyal to God and was steadfast in his faith in God. At the end, the Bible states that God blessed him richly. (Read about Job in the book of Job).
Spiritual battles are fought in our minds. Satan tries to tempt us with ideas that are contrary to God’s word. He does not want to see the word of God working in our lives. He tries to draw us into ungodly areas that our flesh craves. He tempts us with things the flesh lusts after, the lust of the eyes and the pride of life. “In the world you will have trials be of good cheer, I have overcome the world,” John 16:33. We too are over-comers, because greater is He that is in us than he that is of the world (1 John 4:4).