demon. In the O.T. especially, a god. Deut. 32:17; Ps. 106:37; also 1Cor. 10:20.

Usually, in the N.T. an evil or unclean spirit* believed to be the cause of the illness, insanity, or disaster. Matt. 7:22; Mark 1:32; 5:2 (unclean spirit); Luke 8:29; 11:14-15. Demons do not appear in the Gospel of John.

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demon, the English transliteration of a Greek term (daimon) originally referring to any one of numerous, vaguely defined spirit beings, either good or bad. In the nt they are understood as evil spirits, opposed to God and God’s people. In the kjv, the term [daimon] is regularly translated ‘devil,’ a word that appears in the rsv only as the translation of a different Greek term (diabolos) meaning ‘accuser’ or ‘slanderer’. It [diabolos] is used as a virtual synonym for ‘Satan.’

In the ancient world, there was widespread belief in spiritual powers or beings that existed in addition to the well-known gods and goddesses. These beings were not understood as necessarily evil, though some might be. The idea that many or even all such beings were allied with the forces of darkness and wickedness only came into focus, probably under the influence of Persian thought, during the intertestamental period of Judaism.

There are traces of the belief in harmful spirits in the ot writings (e.g., Gen. 6:1-4; Lev. 16:6-10, 26; Isa. 34:14; Job 6:4; Ps. 91:5), but little was made of this idea in Hebrew thought until the late postexilic period. Then, the belief developed that there existed not only numerous evil spirits or demons but also a leader for these evil forces. This leader came to be known in Jewish thought by several titles, though the most common designation was Satan (the Greek title ‘the devil’ was then used as a virtual synonym for Satan, as, e.g., in John 8:44). As a result of this type of thinking, the idea developed that there were armies of demons, under the leadership of Satan or the devil, doing battle with God and God’s allies.

The idea then developed that demons could invade human bodies and personalities and cause mental illness, physical disease, or other specific problems such as deafness or blindness. Some even believed that demons could take control of nature and cause natural calamities and disasters. Such ideology is clearly reflected in the synoptic Gospels of the nt, where Jesus is known as one who characteristically exorcises demons (e.g., Matt. 8:28-34; Mark 5:1-20; Luke 8:26-39; Matt. 12:22-32; Mark 3:22-27; Luke 11:14-23).

The apostle Paul understood the ‘principalities’ and ‘powers’ to be evil forces in this world (Rom. 8:38; cf. Col. 1:16; 2:15; Eph. 3:10; also 1 Cor. 10:20). In some of the later nt writings, however, the place of the demons began to give way to the centrality of the leader of the demonic forces, namely, Satan or the devil (who is sometimes referred to as ‘the evil one’). Thus, in the Fourth Gospel, there are no references to demon possession or exorcism. The devil has become the instigator of evil (e.g., John 13:2), though the charges fly back and forth between the religious authorities and Jesus as to who ‘has a demon’ (John 7:20; 8:48-49; 10:20-21), probably meaning, in the Fourth Gospel, who was thoroughly evil and opposed to God.

The idea that there are evil forces in the world that manifest themselves in various ways is still valid. How one articulates this idea may change from one culture to another, however. Demonology was a part of the culture of the nt world and should be interpreted and understood against that background.

Browse also a relevant textual commentary at http://www.bibletexts.com/versecom/mat10v08.htm.