Romans 8:15 says: For ye have not received the spirit of bondage again to fear; but ye have received the Spirit of adoption, whereby we cry, Abba, Father.
When you were born again, your human spirit was completely recreated. You received all of the qualities, all of your spiritual forces, all of the things of God that Adam had in him when God created him in the Garden of Eden, plus all the things in Jesus when God raised him from the dead.
I want you to notice these words: You have not received the spirit of bondage again to fear. Fear is not a natural force to the born-again believer. It was natural to you before you were reborn, but your spirit man was recreated and eternal life erupted in your heart when you made Jesus the Lord of your life. The reborn human spirit cannot produce fear. It can receive it and act on it and be choked by it, but it cannot produce it.
God is revealing by his word that Satan has lost his authority and power. The name of Jesus will always defeat him. The counterfeit will never win. Faith will always overcome fear. Love will always overcome hate. Prosperity will always overcome poverty.
Fear is a spiritual force, just as faith is a spiritual force. When you apply faith and operate in it by keeping the word of God in your heart, that faith of God will flow through your body to keep it well and whole. When you apply fear and operate in it, the force of fear will work against you to make you sick. Fear works in the spirit world the same as faith.
Fear activates Satan the way faith activates God. Fear is totally destructive. It will cripple the mind, stop the heart, and even change the color of your hair.
Fear is a satanic force that works against you at every opportunity. Faith is a creative force that God uses to build and uplift. Faith helps; fear hurts. Whenever faith is in operation, you will always benefit from it. Whenever fear is in operation, you will be subject to bondage and torment.
You are in concert with Satan in this earth as long as you have five physical senses and a workable mind. He is a thief, a liar, and a killer. He will do his best to destroy you and your testimony as a believer. His goal is to successfully remove you from the field of action. His main weapon in reaching that goal is fear. He wants you to take the opportunity to fear so that you will fail. Satan challenges the promises of God with fear. He tries to make it look as if those promises won't work and that Jesus' sacrifice at Calvary wasn't good enough. He challenges the faith-filled promises of God's word with fear-filled lies of his own.
When Satan comes to us with lies, we must come back at him with the word of God. When he says, "You're never going to be anything because you're scared". You have to open your mouth and say, " For God has not given me the spirit of fear; but of power, and of love, and of a sound mind". God blesses each of us with a mouth and we have to use that mouth to shut down the devil's lies.
Fear is something that one must be willing to diligently fight against. Especially if you have had a past of yielding to fear as I have. 2 Corinthians 10:4 [Amplified version] says: "For the weapons of our warfare are not physical [weapons of flesh and blood], but they are mighty before God for the overthrow and destruction of strongholds". So we have to fight against the spirit of fear with faith which is not a fleshly or carnal weapon.