Demon

Concise Bible Dictionary:

It is to be regretted that the translators of the AV did not use the word “demon” where these words occur instead of “devil,” for which there is another Greek word, διάβολος, signifying “accuser.” This latter word is used only in the singular, referring to the devil—Satan; but there are many demons. Philosophers spoke of demons quite differently from the way they are represented in scripture. Thus Plato says, “Every demon is a middle being between God and the mortal. God is not approached immediately by man, but all the commerce and intercourse between gods and men is performed by the mediation of demons.” This was a device of Satan, that God could be worshipped through the agency of demons or demi-gods. In a similar way the Roman Catholics pray to the Virgin and the saints to intercede for them. Scripture makes it plain that the demons were evil spirits (compare Rev. 16:13-1413And I saw three unclean spirits like frogs come out of the mouth of the dragon, and out of the mouth of the beast, and out of the mouth of the false prophet. 14For they are the spirits of devils, working miracles, which go forth unto the kings of the earth and of the whole world, to gather them to the battle of that great day of God Almighty. (Revelation 16:13‑14)).
Scripture also shows that idolatry was essentially demon-worship, the idol itself being nothing. “They sacrificed unto demons (shed), not unto God” (Deut. 32:1717They sacrificed unto devils, not to God; to gods whom they knew not, to new gods that came newly up, whom your fathers feared not. (Deuteronomy 32:17); 1 Cor. 10:19-2019What say I then? that the idol is any thing, or that which is offered in sacrifice to idols is any thing? 20But I say, that the things which the Gentiles sacrifice, they sacrifice to devils, and not to God: and I would not that ye should have fellowship with devils. (1 Corinthians 10:19‑20)); “they shall no more offer their sacrifices unto demons (sair)” (Lev. 17:77And they shall no more offer their sacrifices unto devils, after whom they have gone a whoring. This shall be a statute for ever unto them throughout their generations. (Leviticus 17:7); Rev. 9:2020And the rest of the men which were not killed by these plagues yet repented not of the works of their hands, that they should not worship devils, and idols of gold, and silver, and brass, and stone, and of wood: which neither can see, nor hear, nor walk: (Revelation 9:20)). Jeroboam had fallen so low as to have ordained priests for the demons (sair) and for the calves which he had made (2 Chron. 11:1515And he ordained him priests for the high places, and for the devils, and for the calves which he had made. (2 Chronicles 11:15)); and some had “sacrificed their sons and their daughters unto demons (shed)” (Psa. 106:3737Yea, they sacrificed their sons and their daughters unto devils, (Psalm 106:37)). The things worshipped may have been unseen objects, or they may have had some mystical representation, or may have been mere idols; but behind all these were real beings, evil, unclean spirits; so that it was morally impossible to have fellowship with the Lord Jesus and with these demons (1 Cor. 10:19-2119What say I then? that the idol is any thing, or that which is offered in sacrifice to idols is any thing? 20But I say, that the things which the Gentiles sacrifice, they sacrifice to devils, and not to God: and I would not that ye should have fellowship with devils. 21Ye cannot drink the cup of the Lord, and the cup of devils: ye cannot be partakers of the Lord's table, and of the table of devils. (1 Corinthians 10:19‑21)).
The evil spirits that possessed so many persons when the Lord was on earth were demons, and from the instances given we learn much respecting them. The Pharisees said that the Lord cast out demons by Beelzebub the prince of demons. The Lord interpreted this to mean “Satan casting out Satan”; by which we learn that the demons were the agents of Satan; and that Satan as a strong man had to be bound before his kingdom could be assailed (Matt. 12:24-2924But when the Pharisees heard it, they said, This fellow doth not cast out devils, but by Beelzebub the prince of the devils. 25And Jesus knew their thoughts, and said unto them, Every kingdom divided against itself is brought to desolation; and every city or house divided against itself shall not stand: 26And if Satan cast out Satan, he is divided against himself; how shall then his kingdom stand? 27And if I by Beelzebub cast out devils, by whom do your children cast them out? therefore they shall be your judges. 28But if I cast out devils by the Spirit of God, then the kingdom of God is come unto you. 29Or else how can one enter into a strong man's house, and spoil his goods, except he first bind the strong man? and then he will spoil his house. (Matthew 12:24‑29)). The demons also were strong ones, by the way they handled those they possessed, and by one overcoming seven men and making them flee out of the house naked and wounded (Acts 19:1616And the man in whom the evil spirit was leaped on them, and overcame them, and prevailed against them, so that they fled out of that house naked and wounded. (Acts 19:16)). We know also that they were intelligent beings; for they knew the Lord Jesus and bowed at once to His authority. They also knew that punishment awaited them: for some asked if the Lord had come to torment them before the time (Matt. 8:2929And, behold, they cried out, saying, What have we to do with thee, Jesus, thou Son of God? art thou come hither to torment us before the time? (Matthew 8:29)).
It must not be supposed that demon-agency has ceased: the exhortation is, “Believe not every spirit, but try the spirits whether they are of God: because many false prophets are gone out into the world” (1 John 4:11Beloved, believe not every spirit, but try the spirits whether they are of God: because many false prophets are gone out into the world. (1 John 4:1)). With this agrees the declaration that “in the latter times some shall depart from the faith, giving heed to seducing spirits and doctrines of demons” (1 Tim. 4:11Now the Spirit speaketh expressly, that in the latter times some shall depart from the faith, giving heed to seducing spirits, and doctrines of devils; (1 Timothy 4:1)). Spiritualists and Theosophists carry on intercourse with such, and are taught by them. In a future day also, when God will be pouring out His judgments on the earth, men will not repent, but will worship demons and all sorts of idols (Rev. 9:2020And the rest of the men which were not killed by these plagues yet repented not of the works of their hands, that they should not worship devils, and idols of gold, and silver, and brass, and stone, and of wood: which neither can see, nor hear, nor walk: (Revelation 9:20)). The spirits of demons also, by working miracles, will gather the kings of the earth together to the battle of that great day of Almighty God (Rev. 16:1414For they are the spirits of devils, working miracles, which go forth unto the kings of the earth and of the whole world, to gather them to the battle of that great day of God Almighty. (Revelation 16:14)). And mystical Babylon will become “the habitation of demons, and the hold of every foul spirit, and a cage of every unclean and hateful bird” (Rev. 18:22And he cried mightily with a strong voice, saying, Babylon the great is fallen, is fallen, and is become the habitation of devils, and the hold of every foul spirit, and a cage of every unclean and hateful bird. (Revelation 18:2)). The world and the professing church are evidently ripening for these things; and some, under the plea of investigating phenomena, are unconsciously having to do with the wicked spirits themselves!