Let me ask you a question: How do you explain the existence of evil, if there is no evil spiritual force working behind the scenes of this world?
After all, evil isn't just an absence of good; evil is real, and evil is aggressive and destructive. Can you come up with a better explanation than the existence of Satan, as he is portrayed in the Bible? I doubt it. The Bible calls him "The great dragon... who leads the whole world astray" (Revelation 12:9). Jesus called him "a murderer from the beginning, not holding to the truth, for there is no truth in him.... he is a liar and the father of lies" (John 8:44).
It has been said that one of the devil's greatest tricks is to make people believe he doesn't exist -- and that's true. When we deny his existence, we become blinded to the reality of evil, and we fall for his lies about God and about ourselves. But Satan is real; our headlines scream it every day.
The most important truth, however, about the devil is this: He is a defeated foe! By His death Jesus overcame Satan's charges against us, and by His resurrection Jesus conquered Satan's rule of death. And some day Christ's victory over Satan will be complete, and Satan and his demons will be banished forever. Don't be deceived, but turn to Jesus Christ and build your life on His truth. He alone can give us hope, both now and forever.