Before the physical realm, God created powerful spirit servants who are referred to in Scripture as angels, literally meaning "messengers" (Hebrews 1:7 Hebrews 1:7And of the angels he said, Who makes his angels spirits, and his ministers a flame of fire.
American King James Version×, Hebrews 1:14 Hebrews 1:14Are they not all ministering spirits, sent forth to minister for them who shall be heirs of salvation?
American King James Version×). Described in some verses as "sons of God" by virtue of their creation by God, they witnessed the formation of the earth (Job 38:4-7 Job 38:4-7 [4] Where were you when I laid the foundations of the earth? declare, if you have understanding. [5] Who has laid the measures thereof, if you know? or who has stretched the line on it? [6] Whereupon are the foundations thereof fastened? or who laid the corner stone thereof; [7] When the morning stars sang together, and all the sons of God shouted for joy?
American King James Version×).

There are hundreds of millions of righteous angels serving God (Revelation 5:11 Revelation 5:11And I beheld, and I heard the voice of many angels round about the throne and the beasts and the elders: and the number of them was ten thousand times ten thousand, and thousands of thousands;
American King James Version×). But a large contingent of angels rebelled against God prior to the creation of mankind. They chose the way of vanity and selfishness instead of God's way of outflowing love for others. The leader of this rebellion is now known as Satan. He and his evil cohorts are referred to in the New Testament as unclean spirits or as demons.

Satan is the adversary of God, as the name Satan actually means "adversary" in the Hebrew of the Old Testament. The Greek Septuagint translation of the Old Testament renders this word as diabolos, from which we get the English word devil. It means "slanderer" and can have the sense of an accuser or opponent in court (compare Zechariah 3:1 Zechariah 3:1And he showed me Joshua the high priest standing before the angel of the LORD, and Satan standing at his right hand to resist him.
American King James Version×). Both the Hebrew and Greek terms are used in the New Testament.

The devil opposes God continually at every opportunity. He despises God's plan, particularly its objective of adding human beings to God's family. Hence, Satan also detests human beings. He is the deceiver and accuser of the brethren (Revelation 12:9-10 Revelation 12:9-10 [9] And the great dragon was cast out, that old serpent, called the Devil, and Satan, which deceives the whole world: he was cast out into the earth, and his angels were cast out with him. [10] And I heard a loud voice saying in heaven, Now is come salvation, and strength, and the kingdom of our God, and the power of his Christ: for the accuser of our brothers is cast down, which accused them before our God day and night.
American King James Version×). He is a murderer and a liar and the father of lying (John 8:44 John 8:44You are of your father the devil, and the lusts of your father you will do. He was a murderer from the beginning, and stayed not in the truth, because there is no truth in him. When he speaks a lie, he speaks of his own: for he is a liar, and the father of it.
American King James Version×). He is described figuratively as a roaring lion seeking whom he may devour (1 Peter 5:8 1 Peter 5:8Be sober, be vigilant; because your adversary the devil, as a roaring lion, walks about, seeking whom he may devour:
American King James Version×).

Satan is not an ordinary opponent. He is an extremely resourceful and cunning adversary whose ultimate goal is to deny salvation to mankind by deceiving people, leading them astray, enticing them to sin and turning them against God (Ephesians 6:11-18 Ephesians 6:11-18 [11] Put on the whole armor of God, that you may be able to stand against the wiles of the devil. [12] For we wrestle not against flesh and blood, but against principalities, against powers, against the rulers of the darkness of this world, against spiritual wickedness in high places. [13] Why take to you the whole armor of God, that you may be able to withstand in the evil day, and having done all, to stand. [14] Stand therefore, having your loins girt about with truth, and having on the breastplate of righteousness; [15] And your feet shod with the preparation of the gospel of peace; [16] Above all, taking the shield of faith, with which you shall be able to quench all the fiery darts of the wicked. [17] And take the helmet of salvation, and the sword of the Spirit, which is the word of God: [18] Praying always with all prayer and supplication in the Spirit, and watching thereunto with all perseverance and supplication for all saints;
American King James Version×; 2 Corinthians 2:11 2 Corinthians 2:11Lest Satan should get an advantage of us: for we are not ignorant of his devices.
American King James Version×; Luke 8:12 Luke 8:12Those by the way side are they that hear; then comes the devil, and takes away the word out of their hearts, lest they should believe and be saved.
American King James Version×).

As the book of Job demonstrates, Satan can act only within the limits permitted by God (Job 1:12 Job 1:12And the LORD said to Satan, Behold, all that he has is in your power; only on himself put not forth your hand. So Satan went forth from the presence of the LORD.
American King James Version×; Job 2:6 Job 2:6And the LORD said to Satan, Behold, he is in your hand; but save his life.
American King James Version×). Job's account also illustrates Satan's accusatory attitude and clearly describes him as a specific individual personality and literal being. As the New Testament shows, he later came to Jesus Christ as a literal being in an unsuccessful effort to tempt Jesus into selfish concern (Matthew 4:1-11 Matthew 4:1-11 [1] Then was Jesus led up of the spirit into the wilderness to be tempted of the devil. [2] And when he had fasted forty days and forty nights, he was afterward an hungered. [3] And when the tempter came to him, he said, If you be the Son of God, command that these stones be made bread. [4] But he answered and said, It is written, Man shall not live by bread alone, but by every word that proceeds out of the mouth of God. [5] Then the devil takes him up into the holy city, and sets him on a pinnacle of the temple, [6] And said to him, If you be the Son of God, cast yourself down: for it is written, He shall give his angels charge concerning you: and in their hands they shall bear you up, lest at any time you dash your foot against a stone. [7] Jesus said to him, It is written again, You shall not tempt the Lord your God. [8] Again, the devil takes him up into an exceeding high mountain, and shows him all the kingdoms of the world, and the glory of them; [9] And said to him, All these things will I give you, if you will fall down and worship me. [10] Then said Jesus to him, Get you hence, Satan: for it is written, You shall worship the Lord your God, and him only shall you serve. [11] Then the devil leaves him, and, behold, angels came and ministered to him.
American King James Version×).

Just as Satan's actions are limited by God's will, his time is also limited. He is presently "the ruler of this world" (John 12:31 John 12:31Now is the judgment of this world: now shall the prince of this world be cast out.
American King James Version×; John 14:30 John 14:30Hereafter I will not talk much with you: for the prince of this world comes, and has nothing in me.
American King James Version×; John 16:11 John 16:11Of judgment, because the prince of this world is judged.
American King James Version×) and described as "the god of this age" (2 Corinthians 4:4 2 Corinthians 4:4In whom the god of this world has 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 to them.
American King James Version×), but his reign will come to an end at the seventh and last trumpet when Jesus Christ returns (1 Corinthians 15:52 1 Corinthians 15:52In a moment, in the twinkling of an eye, at the last trump: for the trumpet shall sound, and the dead shall be raised incorruptible, and we shall be changed.
American King James Version×; 1 Thessalonians 4:16 1 Thessalonians 4:16For the Lord himself shall descend from heaven with a shout, with the voice of the archangel, and with the trump of God: and the dead in Christ shall rise first:
American King James Version×; Revelation 11:15 Revelation 11:15And the seventh angel sounded; and there were great voices in heaven, saying, The kingdoms of this world are become the kingdoms of our Lord, and of his Christ; and he shall reign for ever and ever.
American King James Version×).

Satan will then be removed and bound throughout the millennial reign of the Messiah but will be released for a short while at the end of the 1,000 years (Revelation 20:1-3 Revelation 20:1-3 [1] And I saw an angel come down from heaven, having the key of the bottomless pit and a great chain in his hand. [2] And he laid hold on the dragon, that old serpent, which is the Devil, and Satan, and bound him a thousand years, [3] And cast him into the bottomless pit, and shut him up, and set a seal on him, that he should deceive the nations no more, till the thousand years should be fulfilled: and after that he must be loosed a little season.
American King James Version×; Revelation 20:7-8 Revelation 20:7-8 [7] And when the thousand years are expired, Satan shall be loosed out of his prison, [8] And shall go out to deceive the nations which are in the four quarters of the earth, Gog, and Magog, to gather them together to battle: the number of whom is as the sand of the sea.
American King James Version×). After that he will be permanently removed when he is "cast into the lake of fire and brimstone" (Revelation 20:10 Revelation 20:10And the devil that deceived them was cast into the lake of fire and brimstone, where the beast and the false prophet are, and shall be tormented day and night for ever and ever.
American King James Version×), which is "prepared for the devil and his angels" (Matthew 25:41 Matthew 25:41Then shall he say also to them on the left hand, Depart from me, you cursed, into everlasting fire, prepared for the devil and his angels:
American King James Version×).

Satan was created as an angel of high position and authority. In Isaiah 14:12 Isaiah 14:12How are you fallen from heaven, O Lucifer, son of the morning! how are you cut down to the ground, which did weaken the nations!
American King James Version×he is called in Hebrew Heylel, followed by the distinction "son of the morning." The Latin translation of the name here is given as Lucifer, a name for the planet Venus when appearing as the morning star, meaning "light bearer." Some versions therefore translate the words here as "star of the morning," "bright star" or "morning star" (New American Standard Bible, Revised English Bible, New International Version).

Addressed in Ezekiel 28 as the "king of Tyre," as he is the unseen power behind the throne of earthly kingdoms, this being was initially an "anointed cherub who covers" (Ezekiel 28:14-16 Ezekiel 28:14-16 [14] You are the anointed cherub that covers; and I have set you so: you were on the holy mountain of God; you have walked up and down in the middle of the stones of fire. [15] You were perfect in your ways from the day that you were created, till iniquity was found in you. [16] By the multitude of your merchandise they have filled the middle of you with violence, and you have sinned: therefore I will cast you as profane out of the mountain of God: and I will destroy you, O covering cherub, from the middle of the stones of fire.
American King James Version×), one of two angelic beings whose wings were stretched out over the throne of God, as represented in the earthly copy, the Ark of the Covenant (see Exodus 25:20-21 Exodus 25:20-21 [20] And the cherubim shall stretch forth their wings on high, covering the mercy seat with their wings, and their faces shall look one to another; toward the mercy seat shall the faces of the cherubim be. [21] And you shall put the mercy seat above on the ark; and in the ark you shall put the testimony that I shall give you.
American King James Version×; Hebrews 9:23-24 Hebrews 9:23-24 [23] It was therefore necessary that the patterns of things in the heavens should be purified with these; but the heavenly things themselves with better sacrifices than these. [24] For Christ is not entered into the holy places made with hands, which are the figures of the true; but into heaven itself, now to appear in the presence of God for us:
American King James Version×; Revelation 11:19 Revelation 11:19And the temple of God was opened in heaven, and there was seen in his temple the ark of his testament: and there were lightning, and voices, and thunder, and an earthquake, and great hail.
American King James Version×). He evidently had at least equal rank with Michael, an "archangel" and "great prince" (Jude 1:9 Jude 1:9Yet Michael the archangel, when contending with the devil he disputed about the body of Moses, dared not bring against him a railing accusation, but said, The Lord rebuke you.
American King James Version×; Daniel 12:1 Daniel 12:1And at that time shall Michael stand up, the great prince which stands for the children of your people: and there shall be a time of trouble, such as never was since there was a nation even to that same time: and at that time your people shall be delivered, every one that shall be found written in the book.
American King James Version×).

Lucifer was created perfect and blameless, but eventually chose the way of sin and rebellion (Ezekiel 28:12-17 Ezekiel 28:12-17 [12] Son of man, take up a lamentation on the king of Tyrus, and say to him, Thus said the Lord GOD; You seal up the sum, full of wisdom, and perfect in beauty. [13] You have been in Eden the garden of God; every precious stone was your covering, the sardius, topaz, and the diamond, the beryl, the onyx, and the jasper, the sapphire, the emerald, and the carbuncle, and gold: the workmanship of your tabrets and of your pipes was prepared in you in the day that you were created. [14] You are the anointed cherub that covers; and I have set you so: you were on the holy mountain of God; you have walked up and down in the middle of the stones of fire. [15] You were perfect in your ways from the day that you were created, till iniquity was found in you. [16] By the multitude of your merchandise they have filled the middle of you with violence, and you have sinned: therefore I will cast you as profane out of the mountain of God: and I will destroy you, O covering cherub, from the middle of the stones of fire. [17] Your heart was lifted up because of your beauty, you have corrupted your wisdom by reason of your brightness: I will cast you to the ground, I will lay you before kings, that they may behold you.
American King James Version×). Apparently a third of the angels followed him in his insurrection and with him attempted to overthrow God, but they were defeated and cast down to the earth (Revelation 12:4 Revelation 12:4And his tail drew the third part of the stars of heaven, and did cast them to the earth: and the dragon stood before the woman which was ready to be delivered, for to devour her child as soon as it was born.
American King James Version×; Luke 10:18 Luke 10:18And he said to them, I beheld Satan as lightning fall from heaven.
American King James Version×; Isaiah 14:12-15 Isaiah 14:12-15 [12] How are you fallen from heaven, O Lucifer, son of the morning! how are you cut down to the ground, which did weaken the nations! [13] For you have said in your heart, I will ascend into heaven, I will exalt my throne above the stars of God: I will sit also on the mount of the congregation, in the sides of the north: [14] I will ascend above the heights of the clouds; I will be like the most High. [15] Yet you shall be brought down to hell, to the sides of the pit.
American King James Version×; 2 Peter 2:4 2 Peter 2:4For if God spared not the angels that sinned, but cast them down to hell, and delivered them into chains of darkness, to be reserved to judgment;
American King James Version×). The kingdom of Satan is now characterized by darkness, not light, though Satan is able to deceptively present himself as an angel of light (Luke 22:53 Luke 22:53When I was daily with you in the temple, you stretched forth no hands against me: but this is your hour, and the power of darkness.
American King James Version×; Ephesians 6:12 Ephesians 6:12For we wrestle not against flesh and blood, but against principalities, against powers, against the rulers of the darkness of this world, against spiritual wickedness in high places.
American King James Version×; Colossians 1:13 Colossians 1:13 Who has delivered us from the power of darkness, and has translated us into the kingdom of his dear Son:
American King James Version×; 2 Corinthians 11:14 2 Corinthians 11:14And no marvel; for Satan himself is transformed into an angel of light.
American King James Version×).

Under some circumstances, the devil and his demons are able to gain possession and control of human beings and even animals (Matthew 8:28-33 Matthew 8:28-33 [28] And when he was come to the other side into the country of the Gergesenes, there met him two possessed with devils, coming out of the tombs, exceeding fierce, so that no man might pass by that way. [29] And, behold, they cried out, saying, What have we to do with you, Jesus, you Son of God? are you come here to torment us before the time? [30] And there was a good way off from them an herd of many swine feeding. [31] So the devils sought him, saying, If you cast us out, suffer us to go away into the herd of swine. [32] And he said to them, Go. And when they were come out, they went into the herd of swine: and, behold, the whole herd of swine ran violently down a steep place into the sea, and perished in the waters. [33] And they that kept them fled, and went their ways into the city, and told every thing, and what was befallen to the possessed of the devils.
American King James Version×; Matthew 9:32-34 Matthew 9:32-34 [32] As they went out, behold, they brought to him a dumb man possessed with a devil. [33] And when the devil was cast out, the dumb spoke: and the multitudes marveled, saying, It was never so seen in Israel. [34] But the Pharisees said, He casts out devils through the prince of the devils.
American King James Version×). Satan himself entered and possessed the traitor Judas (Luke 22:3 Luke 22:3Then entered Satan into Judas surnamed Iscariot, being of the number of the twelve.
American King James Version×). Christ, whose authority is greater than Satan's, cast out demons during His ministry on earth and has empowered His duly ordained servants to do the same (Mark 16:17 Mark 16:17And these signs shall follow them that believe; In my name shall they cast out devils; they shall speak with new tongues;
American King James Version×).

Satan is referred to by different names and descriptions that denote some of his evil roles, characteristics and actions. Besides "the devil," he is also called Apollyon and Abaddon, meaning "destroyer" and "destruction," respectively (Revelation 9:11 Revelation 9:11And they had a king over them, which is the angel of the bottomless pit, whose name in the Hebrew tongue is Abaddon, but in the Greek tongue has his name Apollyon.
American King James Version×); Belial, meaning "worthless" or "wicked" (2 Corinthians 6:15 2 Corinthians 6:15And what concord has Christ with Belial? or what part has he that believes with an infidel?
American King James Version×); Beelzebub, the name of a Philistine god meaning "Lord of flies" (Matthew 12:24-27 Matthew 12:24-27 [24] But when the Pharisees heard it, they said, This fellow does not cast out devils, but by Beelzebub the prince of the devils. [25] And Jesus knew their thoughts, and said to them, Every kingdom divided against itself is brought to desolation; and every city or house divided against itself shall not stand: [26] And if Satan cast out Satan, he is divided against himself; how shall then his kingdom stand? [27] And if I by Beelzebub cast out devils, by whom do your children cast them out? therefore they shall be your judges.
American King James Version×, compare 2 Kings 1); the great dragon and serpent (Revelation 12:9 Revelation 12:9And the great dragon was cast out, that old serpent, called the Devil, and Satan, which deceives the whole world: he was cast out into the earth, and his angels were cast out with him.
American King James Version×); the tempter (Matthew 4:3 Matthew 4:3And when the tempter came to him, he said, If you be the Son of God, command that these stones be made bread.
American King James Version×; 1 Thessalonians 3:5 1 Thessalonians 3:5For this cause, when I could no longer forbear, I sent to know your faith, lest by some means the tempter have tempted you, and our labor be in vain.
American King James Version×); and the prince of the power of the air (Ephesians 2:2 Ephesians 2:2Wherein in time past you walked according to the course of this world, according to the prince of the power of the air, the spirit that now works in the children of disobedience:
American King James Version×).