For our struggle is not against flesh and blood, but against the rulers, against the authorities, against the powers of this dark world and against the spiritual forces of evil in the heavenly realms (Ephesians 6:12).
"The devil" is known by various names in scripture -- the tempter, the accuser, Belial, Beelzebub, the prince of this world, etc. All of these refer to the same being who is best known as the serpent or Devil or Satan (Revelation 12:9). Satan is a created being who comes from a class of spiritual beings generally known as angels. Paul lists angels among other created things in Romans 8:37-38. He says in Colossians 1:16 that God created all things visible and invisible through Jesus. Included in this list are unseen thrones, powers, rulers and authorities. Satan, who Jesus calls the "prince of this world", certainly fits into the category of an invisible ruler (John 12:31). At some point following his creation, Satan sinned against God and was summarily punished. Though many speculate, scripture does not record Satan's precise act except that he was lifted up with pride (1 Timothy 3:6). As punishment, Jesus testifies that hell was created for the devil and his angels (Luke 10:18, 2 Peter 2:4, Matthew 25:41).
Mankind first encountered Satan when he appeared to Eve in the form of a serpent. Satan cunningly deceived Eve who in turn gave Adam some of the forbidden fruit thus exposing mankind to sin and death (Genesis 3:1-6). His role in mankind's downfall caused Christ to later describe Satan as a murderous father of lies (John 8:44). A few centuries later, God allowed Satan to tempt Job. To compel Job to curse God the devil aroused bandits, conjured fire from heaven, and stirred up a destructive wind. Job lost his wealth, his servants, and his family. When those measures did not work, Satan inflicted a terrible case of boils that covered Job's body (Job 1-2). The account of Job tells its readers a lot about Satan. Although he operates within God's parameters, Satan will use every means at his disposal to compel those who love truth and righteousness to abandon faith in God.
Satan should not be underestimated or minimized. The archangel Michael, who is roughly equivalent to the devil in power and authority, refused to correct or insult Satan (2 Peter 2:10-11, Jude 8-9). Both Jude and Peter urge their audience to show similar restraint. Satan's power should be respected. Though he is strong, Satan does not force a person to sin against their will. He may expose a person's greatest weakness to persuasive temptations, but the old cliché, "the devil made me do it," finds no basis in scripture. Sin begins with fleshly desire, not with Satan's urgings (James 1:14). It is also worth noting that the devil is a created being, therefore he is not equal to God or Jesus in power. He is not omniscient, omnipresent, or omnipotent. He is powerful, but he can be defeated.
Jesus was sent to this world to destroy the works of the devil (1 John 3:8). Following Jesus' baptism, the Holy Spirit led Him into the desert, "where for forty days He was tempted by the devil" (Luke 4:1-2). Luke goes on to describe Jesus's first temptation as the Messiah when Satan enticed Him with the lusts of the flesh, the lusts of the eyes, and the pride of life. Jesus overcame Satan on this and every other occasion. He was faced with every conceivable type of temptation, yet he remained sinless. Christ's victory over the tempter helps those who follow Him. Jesus Christ clothes the Christian with armor to, "stand against the devil's schemes" (Ephesians 6:10-18). He promises the faithful, "Resist the devil, and he will flee from you" (James 4:8). He assures Christians, "[God] will not let you be tempted beyond what you can bear. But when you are tempted, he will also provide a way out so that you can stand up under it" (1 Corinthians 10:13). The disciple knows they can defeat Satan, "because the one who is in you is greater than the one who is in the world" (1 John 4:4). A Christian does not face Satan unaided or defenseless. They are protected and empowered by Jesus Christ.
By overcoming temptation to the point of death, Jesus liberates His followers from their enslavement to sin by assuring eternal life following death. The fear of death is Satan's most potent weapon.
Since the children have flesh and blood, he too shared in their humanity so that by his death he might destroy him who holds the power of death--that is, the devil--and free those who all their lives were held in slavery by their fear of death (Hebrews 2:14-15).
Jesus said to Martha in John 11:25-26, "I am the resurrection and the life. He who believes in me will live, even though he dies; and whoever lives and believes in me will never die." Life beyond death is impossible without Jesus. In fact all one can expect is further death. However, Jesus pledges to His believers that though they die they will live eternally. The death and resurrection of Jesus removes the sting from Satan's mightiest arrow. "Where, O death, is your victory? Where, O death, is your sting?" (1 Corinthians 15:55). Jesus gives the victory over Satan's greatest weapon.