The Father (God) said the enemy is FEAR (a terror) and nothing more!

Fear of God as almighty is reverence toward God because He is God. The born again (saved) know Him as their Father. Any fear other than a righteous fear of God comprises the enemy's spirit of fear that God is insufficient because the Spirit of God is perfect love and all-sufficient. 

• There is no fear in love; but perfect love casteth out fear: because fear hath torment. He that feareth is not made perfect in love. 1 John 4:18. 

Our will of man governs the disposition of our soul by choosing eternal life according to the will of God (the Spirit) or eternal death according to the will of our flesh that dies when our body dies. The enemy works through our will of the flesh; it is literally the enemy's "outside-in" inroad into man.

The enemy's spirit of fear (also called the spirit of error) manifests in man through the will of the flesh in literally any way he lets it. Whenever someone thinks God is insufficient for them, the will of their flesh has opened the door for the enemy to come in. This happens when someone leaves the Word and/or abandons the truth of it. Interlineated for clarity with text in [brackets].:

• For the mystery of iniquity doth already work: only he who now letteth will let, until he be taken out of the way. And then shall that Wicked be revealed, whom the Lord shall consume with the spirit of his mouth [the Word], and shall destroy with the brightness of his coming: Even him, whose coming is after the working of Satan with all power and signs and lying wonders, And with all deceivableness of unrighteousness in them that perish; because they received not the love of the truth, that they might be saved. 2 Thessalonians 2:7-10.

Fear is the only tactic of the enemy, the god of sin and death, because fear is the only spirit it has/is. The enemy was constrained by God the Father to inhabit only that state of existence.

The enemy, the spirit of fear that God is insufficient or not almighty, gains access into us through our mind first when we doubt God is almighty and all-sufficient. Of course, those thoughts are lies. The enemy is a liar and the father of lies.

• Ye are of your father the devil, and the lusts of your father ye will do. He was a murderer from the beginning, and abode not in the  truth, because there is no truth in him. When he speaketh a lie, he speaketh of his own: for he is a liar, and the father of it. John 8:44.

A fear God is insufficient is the pathway to hell. Recall that the devil became the devil because of it. 

Anyone who falls victim to the enemy's spirit of fear is blinded and is, by definition, fearful that God is in some way not powerful enough, not loving enough, not sound in mind, not good enough, not fun enough, not strong enough, not satisfying enough, etc., and not the best choice. If they didn't have a bogus fear that God is inadequate, they would choose the ways of God over the enemy in an instant.

• Love not the world, neither the things that are in the world. If any man love the world, the love of the Father is not in him. For all that is in the world, the lust of the flesh, and the lust of the eyes, and the pride of life, is not of the Father, but is of the world. And the world passeth away, and the lust thereof: but he that doeth the will of God abideth for ever. Little children, it is the last time: and as ye have heard that antichrist shall come, even now are there many antichrists; whereby we know that it is the last time. They went out from us, but they were not of us; for if they had been of us, they would no doubt have continued with us: but they went out, that they might be made manifest that they were not all of us. 1 John 2:15-19.

The enemy is powerless over the born again, the elect, who live by the Spirit! However, even the very elect may be deceived by false prophets and false Christs if they do not know the truth.  

• For there shall arise false Christs, and false prophets, and shall shew great signs and wonders; insomuch that, if it were possible, they shall deceive the very elect. Matthew 24:24.

God said the pure Word is the way we resist all evil including false prophets and false Christs.

Yes. God in heaven does not do evil. All evil is based on a sentiment that God is not almighty, sovereign, all-sufficient, etc., as explained in detail below. The enemy is the god of this world. The god of this world is the devil. The devil is the evil spirit that roams the earth. Beware:

• But if our gospel be hid, it is hid to them that are lost: In whom the god of this world hath blinded the minds of them which believe not, lest the light of the glorious gospel of Christ, who is the image of God, should shine unto them. (Emphasis added) 2 Corinthians 4:4. 

Thus, despite what some people choose to believe, God the Father in Heaven is not the “god of this world.”

From God's perspective as the almighty sovereign, evil is a belief that He (God or His will) are in some way insufficient for us. For example, rejecting Jesus or the Word of God is a rejection of God the Father. Rejecting God makes you His adversary because you side with the god of this world as a friend of it.

• ...know ye not that the friendship of the world is enmity with God? whosoever therefore will be a friend of the world is the enemy of God. James 4:4.
• God is jealous, and the Lord revengeth; the Lord revengeth, and is furious; the Lord will take vengeance on his adversaries, and he reserveth wrath for his enemies. Nahum 1:2.

The enemy, the devil, knows God will destroy it and all who rise up against Him thinking in their heart that God is insufficient in some way, for they are His enemy who shall receive His wrath. The target of the enemy is mankind but the enemy has no power against God (or the born again).

• Behold, I give unto you power...over all the power of the enemy: and nothing shall by any means hurt you. Luke 10:19.

God calls the devil a thief, among other things.

• The thief cometh not, but for to steal, and to kill, and to destroy: I am come that they might have life, and that they might have it more abundantly. John 10:10.

The devil seeks to devour everyone.

• Be sober, be vigilant; because your adversary the devil, as a roaring lion, walketh about, seeking whom he may devour: 1 Peter 5:8.

Please note: God is your loving Father if you want Him to be, or He is your adversary if you reject Him. It's up to you. Choose to become born again (saved) and a child of the almighty God.

We were made in the image and likeness of God, and we have the power to become sons of God. The devil is the enemy of God and the enemy of the Father's children, starting with the Jews and Jesus.

The devil knows the pathway to destruction is challenging God's sufficiency. The Word of God is God, and the Word promises salvation for the believer according to the Father's will. The devil challenges the Word of God that promises salvation for the believer, and the enemy tempts humans to do the same. 

Remember, the devil is fear per se (in itself), but the children of the Father are born again by the Holy Spirit of power (the Holy Ghost), love (the Father), and a sound mind (the Word-the mind of Christ).

• For God hath not given us the spirit of fear; but of power, and of love, and of a sound mind. 2 Timothy 1:7.

Temptation to sin and nothing more. People sin because they want to. Stated another way, they sin because they prefer the will of the flesh and are fearful the ways (will) of God are insufficient to please them. In truth, the ways (will) of God is all important and all-sufficient!

• Be sober, be vigilant; because your adversary the devil, as a roaring lion, walketh about, seeking whom he may devour: Whom resist stedfast in the faith, knowing that the same afflictions are accomplished in your brethren that are in the world. 1 Peter 5:8-9.
• In whom the god of this world hath blinded the minds of them which believe not, lest the light of the glorious gospel of Christ, who is the image of God, should shine unto them. 2 Corinthians 4:4.
• Ever learning, and never able to come to the knowledge of the truth. 2 Timothy 3:7.
• And with all deceivableness of unrighteousness in them that perish; because they received not the love of the truth, that they might be saved. 2 Thessalonians 2:10.

The enemy, the devil, uses anyone and/or anything it can to tempt your flesh to fear God's ways (His will) is not the best for you, thereby causing you to separate yourself from complete faith in the sufficiency of God and/or His ways. The devil's approach is only through the flesh (body and mind) because the Spirit gives life.

• For they that are after the flesh do mind the things of the flesh; but they that are after the Spirit the things of the Spirit. Romans 8:5.
• For the flesh lusteth against the Spirit, and the Spirit against the flesh: and these are contrary the one to the other: so that ye cannot do the things that ye would. Galatians 5:17.
• For he that soweth to his flesh shall of the flesh reap corruption; but he that soweth to the Spirit shall of the Spirit reap life everlasting. Galatians 6:8.

Anyone who is not born again of the Spirit is easily manipulated by the devil.

• And the servant of the Lord must not strive; but be gentle unto all men, apt to teach, patient, In meekness instructing those that oppose themselves; if God peradventure will give them repentance to the acknowledging of the truth; And that they may recover themselves out of the snare of the devil, who are taken captive by him at his will. 2 Timothy 2:24-26.

Recall that the enemy (the devil) can only give that which it has as the god of this world. It is the spirit of fear (error). The devil uses itself, the spirit of error, to suggest the Father, His Word, and/or His Spirit of truth (the Holy Ghost) is not almighty and sovereign. The enemy tempts people to believe the same way based on a fear a lifestyle guided by the will of God will be unfulfilling. Our flesh is the target. Our will of the flesh is the inroad.

Mankind is corruptible by nature because he is of the flesh and naturally desires the pleasures of his body, which he knows very well. Whereas faith is required to prefer the ways (will) of God because faith overcomes a personal fear that God's ways are not as desirable as the ways of this world and the flesh.

• For if ye live after the flesh, ye shall die: but if ye through the Spirit do mortify the deeds of the body, ye shall live. Romans 8:13.

An unbeliever of the Word (God) or the sufficiency of the Father's ways (will), shall look to the world for satisfaction. In doing so, they rely on the sufficiency of their flesh to decide what is good and befriend the world to get "it". As a friend of the world they become an enemy from God and shall be destroyed.

• ...know ye not that the friendship of the world is enmity with God? whosoever therefore will be a friend of the world is the enemy of God. James 4:4.
• ...Neither give place to the devil. Ephesians 4:27.

The enemy has no actual power over the born-again, because we do not live in fear of death or anything short of it. Our flesh may experience "dread" because sin dwells in the flesh and dreads its eventual demise, but we do not fear because we are born of the Spirit and live forever. The enemy uses dread in our flesh to lead (tempt) us into fear, receiving him because the enemy is the spirit of fear.

The children of God live courageously by the Word, the Spirit of Truth, in pursuit of the will of the Father, having faith in Him. The enemy is a tempter who tries to get people to think God, His Word, the truth of the scriptures, or His ways are inadequate or insufficient. The enemy tempts our flesh with dread and lets us take on fear whenever we choose to think God is not sufficient to protect us. It tries that with everyone. Think of it this way, those who are dreadful become fearful.

Jesus is a son of God. He has/had the power over all the power of the enemy. When we become born again, we become sons of God through Jesus-the Word, and have the power He has by living in Him, the Word

Therefore, the power to become a son of God IS the way to receive the "power to tread on serpents and scorpions, and over all the power of the enemy," and Jesus gave it to us if we believe Him.

• But as many as received him, to them gave he power to become the sons of God, even to them that believe on his name... John 1:12.

The source is the Spirit of God.

The born again (the saved when our bodies die) are members of the true Royal Family of the Father in the Spirit. We know the Father as our father-Father, as a son in the Spirit, and Jesus as our Brother. We have the authority of the family, the true Royal Family to do our Father's will here on earth in Jesus's stead!

• Verily, verily, I say unto you, He that believeth on me, the works that I do shall he do also; and greater works than these shall he do; because I go unto my Father. John 14:12.
• Now then we are ambassadors for Christ, as though God did beseech you by us: we pray you in Christ's stead, be ye reconciled to God. 2 Corinthians 5:20.

Yes! The Bible says we live "in Him" and get what he has/had. When you became born again of the Spirit, you became a child of God in the Spirit. As a child of God, you are a new creation and have the power to tread on serpents and scorpions and over all the power of the enemy, and nothing by any means shall hurt you. 

Remember, the will of our Father is knowing we are His children, the born again of His Spirit. His Spirit most assuredly has THE power over all the power of the enemy. Of course, if you don't believe it, then the enemy has again deceived you into thinking the ways of the Father are insufficient for you. Don't be duped.

As the born again, you and I do the will of the Father here, and we glorify Jesus whenever we do. Of course, we rejoice in the fact our name is written in the Book of Life and that we live forever and praise Jesus for it. Thus, how "bad" can a "bad day" ever be for us who live forever in heaven when our body dies?