In the Old Testament, the tempter and originator of evil is called the “serpent”(Gen. 3:1-15). [Rev. 12:9 identifies “that old serpent” as Satan.] In Job, he is the accuser (Job 1:6). The word satan means “accuser” or “adversary”in Hebrew. Whenever mentioned in the Old Testament, Satan is always in opposition to the best interests of humans (I Chron. 21:1; Zech. 3:1; Ps. 109:6).
In the New Testament, Satan is mentioned often as the personification of evil. [There are more than 60 references to Satan or the devil and other references to demons and evil spirits.] His actions are calculated to bring people within his sphere of influence. He is opposed to God and God’s redemptive plan for the world (Matt. 13:37-43). Jesus successfully resisted Satan’s temptations, and Satan departed from him for a season (Lk. 4:13). The Gospels show Satan’s continuing work against people through demonic influence and the possession of people by demons (also called agents of Satan). During his public ministry, Jesus showed his dominion over Satan through the casting out or exorcism of demons from certain people, and he accomplished this by virtue of the Spirit of God (Matt. 12:28). Other names for Satan in the New Testament are “Beelzebub”(“lord of filth”), the “tempter,” the great “dragon,””the father of lies,” “the evil one,” “prince (ruler) of this world,””prince of the power of the air,” and “murderer.”
Jesus declared a complete victory over Satan, saying that Satan has already been judged. The book of Revelation discloses the execution of this judgement through consignment of Satan to the lake of fire along with death and Hades (Rev. 20:10,14). Until then, Satan’s operations are limited. While he, “as a roaring lion, walks about seeking whom he may devour,”vigilance in the faith provide protection. If Satan is resisted in his efforts, he will flee (Jas. 4:7). In the words of Paul, our struggle in this world is not with flesh and blood, but with the devil and his minions (principalities and powers) who perpetrate wickedness in high places. The defense against these denizens of evil is in the putting on of the whole spiritual armor of God (Eph. 6:11-13).