Whether you have become a Christian or not, you have a powerful enemy you have never seen. His name is Satan, otherwise known as the devil. You don't believe he's real? That doesn't change a thing, and only makes his job easier. When people think he's only a cute little cartoon character with horns and a pointed tail, they certainly aren't going to be on their guard against him.
Who is he, and where did he come from? He is a fallen angel, who was cast out of Heaven. And he is not alone.
And there was war in heaven, Michael and his angels waging war with the dragon. The dragon and his angels waged war, and they were not strong enough, and there was no longer a place found for them in heaven. And the great dragon was thrown down, the serpent of old who is called the devil and Satan, who deceives the whole world; he was thrown down to the earth, and his angels were thrown down with him. (Revelations 12:7-9)
He and his fellow satanic spirits are your enemies because they are determined to keep you out of the place they will never return to. Satan will work every angle he possibly can to accomplish this task. If you are not a Christian, he will attempt to keep you from becoming one. And if you are a Christian, he will do everything in his power to turn you away from following Christ.
Be of sober spirit, be on the alert. Your adversary, the devil, prowls around like a roaring lion, seeking someone to devour. (1 Peter 5:8)
He is a formidable foe. He has had thousands of years of experience deceiving human beings, and you are no match for him. For those who are not under the protection of God as His children, we can offer you no advice as to how you can be safe from his damaging influence except to become born-again believers. For believers, we offer the following as a help in dealing with your spiritual adversary.
First of all, it always helps to know your enemy and his traits.
He is not human
For our struggle is not against flesh and blood, but against the rulers, against the powers, against the world forces of this darkness, against the spiritual forces of wickedness in the heavenly places. (Ephesians 6:12)
Part of the challenge of being a successful Christian is learning to live on the spiritual plane when you've been so used to living for the most part only on the physical plane. You must become skilled at defeating the incursions of demonic spirits on the plane they exist upon through the power of God within you.
He is not omniscient, omnipresent, or omnipotent
In a word, he is not God. While he is indeed intensely powerful and the very fount of evil influence in this world, don't ascribe to him more power than he actually has.
He can appear to be something he is not
No wonder, for even Satan disguises himself as an angel of light. (2 Corinthians 11:14)
He may come to you in the form of a proponent of Christianity, a friend of God. You must learn to discern between his spirit and the Spirit of the Lord by leaning on the latter to guide you and give you understanding.
He will attempt to twist God's words
And he said to the woman, "Indeed, has God said, 'You shall not eat from any tree of the garden'? You surely will not die! For God knows that in the day you eat from it your eyes will be opened, and you will be like God, knowing good and evil." (Genesis 3:1,4-5)
He will take God's direction to you, and the words of the Bible, and attempt to make them mean something altogether different than God intended. Again, discernment between God's Spirit and the spirit of Satan is critical.
He is a liar
...for he is a liar and the father of lies. (John 8:44)
Knowing the Bible and heeding the warnings of the Spirit of God are our weapons against his chicanery.
Once knowing your foe, you are in a better position to defeat him. The key thing to remember is this: Let God deal with him. As we stated before, you cannot overcome him with your own strength and wisdom. When he knocks on your door to attack you, discourage you, tempt you, or whatever, don't answer it. Let the Lord meet him and conquer him.
Many believers get into trouble by failing to heed this simple advice. They will instead invite Satan in, offer him a seat on the couch, and begin to converse with him. Bad idea. Don't give him the time of day. Ignore him. The Bible tells us, "Resist the devil and he will flee from you" (James 4:7). It works. Be consistent in your refusal to be drawn into conversation with him.
And here's something more that mature Christians can use that really annoys him: Laugh at him. Thomas More of the sixteenth century wrote, "The Devil, the proud spirit, cannot endure to be mocked." He wants to be worshipped and feared, so when we afford him no respect and let him know he is a loser destined for Hell, he leaves in anger. New believers should avoid this tactic as he is more likely to launch a fearsome attack on those who have offended his dignity, but who are not yet skilled at spiritual warfare.
So how can you know whether it's Satan or God speaking to you? This isn't easy for new believers. All kinds of thoughts can be swirling around in their minds, and they often have difficulty discerning who is speaking to them. But you can learn whose voice is whose, and it's critical that you do.
Satan tends to harangue. He is loud. He is grating. He often repeats his insinuations and poisonous suggestions over and over and over. You feel a sense of unease when he is talking to you. And if you stop and really consider what he is urging you to think or do, you will see that it isn't leading toward God and holiness. He will come up with a thousand angles as to why you shouldn't obey God, and isn't above contradicting himself in hopes of finally getting you to bite down on his poison pill.
God speaks with a singular, quiet voice. He doesn't repeat Himself until time has passed and you have yet to heed Him. Even then, He will never enter into a tirade. He always speaks in agreement with the Bible, never against it. His words lead you toward light and good. They build up, rather than tear down. And you will sense His presence when He is speaking.
All this takes time to learn. You will make mistakes. But don't despair, just keep pressing on, always calling on God for wisdom to better meet Satan's challenges in the future. Be always mindful that, "greater is He who is in you than he who is in the world" (1 John 4:4). Keep your hand in Christ's, and no one that rises against you will ever prevail.
Scripture quotations taken from the NASB