The term "devil" is often used synonymously with the term Lucifer or Satan, although Satan has the connotation of a personal evil while the devil is a common name for demons or evil spirits.
The word has its origins with the early Hebrews during the Exodus from Egypt. The local religions they encountered when they entered into Canaan included tales of the demon spirits (sa ir שעירים, "hairy ones" or "saytrs", Isaiah 13:21) of the desert, whose influence could be averted due to sacrifice. Despite being told to "...put away the gods which your fathers served on the other side of the flood, and in Egypt; and serve ye the LORD," (Joshua 24:14) many had accepted this superstition and sacrificed goats on the Canaanite and other altars. From this came the Herew word ha-satan שָׂטָן, the root word of "Satan".
In Christianity, the Devil is named Satan, and sometimes Lucifer. He is a fallen angel who rebelled against God—and also the one who spoke through the serpent and seduced Eve into disobeying God's command. His ultimate goal is to lead people away from the love of God—to lead them to fallacies which God opposes. Satan is also identified as the accuser of Job, the tempter in the Gospels, the secret power of lawlessness in 2 Thessalonians 2:7, and the dragon in the Book of Revelation. Before his insurrection, Satan was among the highest of all angels and the "brightest in the sky". His pride is considered a reason why he would not bow to God as all other angels did, but sought to rule heaven himself.
He is called "the ruler of the demons" (Matt. 12:24), "the ruler of the world" and "the god of this world". (2 Cor. 4:4). The Book of Revelation describes how Satan will be cast out of Heaven, down to the earth, having "great anger" and waging war against "those who obey God's commandments and hold to the testimony of Jesus". Ultimately, Satan is thrown into the "Lake of fire", not as ruler, but as one among many, being tormented day and night forever and ever.
Christian teachings about the devil in the Old Testament include these passages:
The Serpent (Genesis 3)
The devil's first appearance in the Old Testament is as the serpent in the Garden of Eden. The serpent tempts Adam and Eve into eating the fruit of the Tree of Knowledge of Good and Evil, which God had forbidden them to eat, thus causing their expulsion from the Garden and indirectly causing sin to enter the world. In God's rebuke to the serpent, he tells it "And I will put enmity between thee and the woman and between thy seed and her seed; it shall bruise thy head and thou shalt bruise his heel" (Genesis 3:14-15). In another translation it says, "I will put enmities between thee and the woman, and thy seed and her seed: she shall crush thy head, and thou shalt lie in wait for her heel" (Genesis 3:15). Ipsa, the woman; so divers of the fathers read this place, conformably to the Latin: others read it ipsum, viz., the seed. The sense is the same: for it is by her seed, Jesus Christ, that the woman crushes the serpent's head.
Scriptures are often interpreted to identify the serpent with the Devil. The deuterocanonical Book of Wisdom says, "But by the envy of the devil, death entered the world and they who are in his possession experience it" (Wisdom 2:24). Satan is implicitly identified, in the New Testament, with the serpent in Eden, in Revelation 12:9: "This great dragon — the ancient serpent called the Devil, or Satan, the one deceiving the whole world — was thrown down to the earth with all his angels."
Job's adversary (Job 1)
Christian teaching about the Satan (Hebrew שָׂטָן, Adversary), to whom God proposes his servant Job is that he appears in the heavenly court to challenge Job, with God's permission. This is one of two Old Testament passages, along with Zechariah 3, where Hebrew ha-Satan (the Adversary) becomes Greek ho diabolos (the Slanderer) in the Greek Septuagint used by the early Christian church.
David's satan (2 Sam 24. & 1 Chron. 21)
Christian teaching about the involvement of Satan in David's census (a practice explained in Exodus 30:11–16), varies, just as the pre-exilic account of 2 Samuel and the later account of 1 Chronicles present differing perspectives:
2 Samuel 24:1 "And again the anger of the LORD was kindled against Israel, and he moved David against them to say, Go, number Israel and Judah"
1 Chronicles 21:1 "Satan stood up against Israel and moved David to number Israel."
Zechariah's vision of recently deceased Joshua the High Priest depicts a dispute in the heavenly throne room between Satan and the Angel of the Lord Zechariah 3:1 "Then he showed me Joshua the high priest standing before the angel of the LORD, and Satan standing at his right side to accuse him."
Azazel (Leviticus 16)
Some see the Scapegoat (Hebrew Azazel) : Leviticus 16:8 "And Aaron shall cast lots over the two goats, one lot for the LORD and the other lot for the scapegoat" / for Azazel." Also, Leviticus 16:10 Leviticus 16:26 as relating to Satan.
Isaiah's Lucifer (Isaiah 14)
Since the time of Origen and Jerome some Christian concepts of the devil have included the Morning Star in Isaiah 14:12, which is translated Lucifer "Light Bringer" in the Latin Vulgate, and directly from Latin into the Douay-Rheims as a name "Lucifer"
Cherub in Eden (Ezekiel 28)
Ezekiel 28 is thought by some to be referring metaphorically to Satan as well as to the king of Babylon.
New Testament references include:
The Devil - (Greek ho diabolos) : Following the use in Job and Zechariah in the Septuagint this title, "the Accuser", is ascribed to Satan 32 times in the New Testament. The three other uses of the word are for humans - Judas, and gossips.(Revelation 12:9).
Satan - (Greek ho satanas): Luke 10:18 "I saw Satan fall like lightning from heaven." See also Matthew 4:10; Matthew 12:26; Mark 4:15; Luke 22:31; Acts 26:18; 1 Corinthians 5:5; 2 Corinthians 11:14; 1 Thessalonians 2:18; 1 Timothy 5:15; Revelation 3:9; Revelation 20:2.
Beelzebub - (Greek Beelzeboul) : In Matthew 10:25, Matthew 12:24, Mark 3:22, and openly in Luke 11:18-19 there is an implied connection between Satan and Beelzebub (originally a Semitic deity called Baal, and referred to as Baal-zebul, meaning lord of princes). Beelzebub (lit. Lord of the Flies) has now come to be analogous to Satan.
The Wicked One - (Greek ho poneros) : Matthew 13:19 "Then cometh the wicked one." Matthew 6:13, 1 John 5:19. This title suggests that Satan is one who is wicked himself. Abrahamic religions generally regarded sin as a physical manifestation of opposition to God, and therefore evil; dissent only comes from the topic of 'where does sin come from?'
Prince of this World - (Greek ho Archōn tou kosmou toutou, Latin Rex Mundi) : in John 12:31 and John 14:30.
The Tempter - (Greek ho peirazōn) : Matthew 4:3 "And when the tempter came to him." Also, 1 Thessalonians 3:5.
A liar - (Greek psěustēs) : John 8:44 "He is a liar and the father of it."
Belial - (Greek Belial) : in 2 Corinthians 6:15 "What agreement does Christ have with Belial?" may be a reference to the Devil, or to eating idol meats. In the Old Testament, rebellious people and nonbelievers are sometimes called 'sons of Belial'. See also Deuteronomy 13:13; Judges 20:13; 1 Samuel 2:12; 2 Samuel 23:6; 1 Kings 21:10; 2 Chronicles 13:7.
The god of this world in 2 Corinthians 4:4.
The prince of the power of the air in Ephesians 2:2.
Your adversary - (Greek antidikos) : in 1 Peter 5:8 "Your adversary the devil." In the Christian worldview, Satan is the adversary of both God and the believers.
The Dragon - (Greek ho drakōn) : in 2 Revelation 20:2.
The Ancient Serpent - (Greek ho ophis ho archaios) : also in 2 Revelation 20:2.
The Devil figures much more prominently in the New Testament and in Christian theology than in the Old Testament and Judaism. The New Testament records numerous accounts of the Devil working against God and his plan. The Temptation of Christ features the Devil, and is described in all three synoptic gospels, (Matthew 4:1-11, Mark 1:12-13, and Luke 4:1-13), although in Mark's gospel he is called Satan. In all three synoptic gospels, (Matthew 9:22-29, Mark 3:22-30, and Luke 11:14-20), Jesus' critics accuse him of gaining his power to cast out demons from Beelzebub, the chief demon (often identified with Satan in mainstream Christendom). In response, Jesus says that a house divided against itself will fall, so, logically speaking, why would the Devil allow one to defeat the Devil's works with his own power?
There are numerous incidences of demonic possession in the New Testament. Satan himself is said to have entered Judas Iscariot before Judas's betrayal. (Luke 22:3) Jesus encounters those who are possessed and casts out the evil spirit(s). A person may have one demon or multiple demons inhabiting their body. Jesus encountered a man filled with numerous demons in Mark 5:1-20.
Acts & Epistles
In the New Testament, Letter of Jude (Jude 1:9) reference is made to the Archangel Michael arguing with the Devil over the body of Moses.
Revelation / Apocalypse
The Book of Revelation or Apocalypse describes how Satan will be cast out of Heaven, down to the earth, having "great anger" and waging war against "those who obey God's commandments and hold to the testimony of Jesus". Ultimately, Satan is thrown into the "Lake of fire", not as ruler, but as one among many, being tormented day and night forever and ever.
The Book of Revelation twice refers to "the dragon, that ancient serpent, who is called the devil and Satan," (12:9, 20:2). The Book of Revelation also refers to "the deceiver," from which is derived the common epithet "the great deceiver."
Devil is a synonym for Satan / Ha-Satan, which descends from the Middle English devel, from Old English dēofol, that in turn represents an early Germanic borrowing of Latin diabolus (also the source of "diabolical"). This in turn was borrowed from Ancient Greek diábolos (διάβολος), "slanderer", from diaballein "to slander": dia- "across, through" + ballein "to hurl". In the New Testament, "Satan" occurs more than 30 times in passages alongside diábolos (Ancient Greek for "the devil"), referring to the same person or thing as Satan.
In some religions and traditions, these titles are separate demons; others identify these names as guises of The Devil. Even when thought of as individual demons, some are often thought of being under the Devil's direct control. This identifies only those thought of as the Devil.
Azazel, Asael (Hebrew): King of Devils
Baphomet, a demon supposedly worshiped by the Knights Templar
Beelzebub, ba'al zevuv בעל זבוב (Hebrew): Master of the flies or Lord of the Flies (Matthew 10:25)
Belial, Beliar, Bheliar (Hebrew): without master, despicableness of the earth, Lord of Pride (2 Corinthians 6:15)
Mastema, a devil in the Book of Jubilees
Sammael, Samiel, Sammael (Hebrew): "Poison of God"
These are titles that almost always refer to the Devil.
666, the Number of the Beast
Angra Mainyu, Ahriman: "malign spirit", "unholy spirit"
Antichrist, the coming of the Devil to the mortal world in Christianity
Der Leibhaftige (German): "He Himself"
Diabolus, Diabolos (Greek: Διάβολος): "cutting through"
Iblis, the devil in Islam
Lord of the underworld / Lord of Hell / Lord of this World
Lucifer / The Morning Star (Greek and Roman): bringer of light, illuminator; the planet Venus, often portrayed as Satan's name before he fell
Mephistopheles, he who avoids the light (φῶς)
Old Scratch, The Stranger, Old Nick: a colloquialism for the devil
Prince of Darkness / Air
Satan / The Adversary, Accuser, Prosecutor
(The ancient/old/crooked/coiling) Serpent
Shaitan, an Arabic name for Satan
Voland (medieval France)
A number of prayers and practices against the Devil exist within the Roman Catholic tradition. The Lord's Prayer includes a petition for being delivered from Evil, but a number of other specific prayers also exist.
The Prayer to Saint Michael specifically asks for Catholics to be "defended in the day of battle", referring to the battle in War in Heaven when Saint Michael the Archangel defeats Satan. This prayer was added to the Leonine Prayers by Pope Leo XIII in 1888 and continued in the Low Mass until the Leonine Prayers themselves were suspended. The Chaplet of Saint Michael is also used as a prayer against the Devil.
The battle against the devil, which is the principal task of Saint Michael the archangel, is still being fought today, because the devil is still alive and active in the world. The evil that surrounds us today, the disorders that plague our society, man's inconsistency and brokenness, are not only the results of original sin, but also the result of Satan's pervasive and dark action.
The process of exorcism is used within the Catholic Church against the Devil. Catholic history and tradition teaches that Jesus performed exorcisms and from him the Church has received the power and office of exorcizing.
Father Gabriele Amorth (who sadly is a Vatican II adherent), the chief exorcist of the [Vatican II] Diocese of Rome, warned about ignoring Satan, saying, "Whoever denies Satan also denies sin and no longer understands the actions of Christ". He also said that Satan is active in such current media as the Harry Potter books and films.
The Catholic Church regards the Devil as being created as a good angel by God, and by his and his fellow fallen angels choice fell out of God's grace.
Satan is not an infinitely powerful being. Although, he was an angel, and thus pure spirit, he is considered a creature nonetheless. Satan's actions are permitted by divine providence.