rom the fourth Century Lucifer is sometimes used in Christian theology to refer to Satan, as a result of identifying the fallen "son of the dawn" of Isaiah 14:12 with the "accuser" of other passages in the Old Testament.
Satan as depicted in the Ninth Circle of Hell in Dante Alighieri's Inferno, illustrated by Gustave Doré
In traditional Christian understanding of the holy Hebrew scriptures, the Torah, Satan is a synonym for the Devil. For most Christians, he is believed to be an 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. The popularly held beliefs that Satan was once an angel who becomes prideful and eventually rebels against God, however, are not portrayed explicitly in the Bible and are mostly based on inference (e.g., Ezekiel 28 and Isaiah 14:12–17). In mainstream Christianity he is called "the ruler of the demons" (Matthew 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.