According to Scripture demons are new gods. They are men who were once famous kings or rulers but died. Their memories are worshiped as though they yet lived as spirits. They don’t! Notice that the rulers of Isaiah 26:13 are dead (Isaiah 26:14) and cannot rise to do harm ever again. The idea that former evil men (new gods) arose as demons (Deuteronomy 32:17) to afflict people again is shown to be false by Isaiah.
The Hebrew word in Deuteronomy is shedim (H7700) and means demon, i.e. malignant, according to Strongs Greek Lexicon. The only other place where shedim (H7700) appears in the Old Testament is at Psalm 106:37. There, the Scriptures record that Israel sacrificed their children to idols (Psalm 106:36), and the idols in this verse become demons in Psalm 106:37. Therefore, the Scriptures make it clear that demons are dead men, one time famous rulers whose memory the ancients worshiped, as though those evil men yet lived. They didn’t! So where did the Jews of Jesus’ day get the idea that demons were living, sentient, malevolent spirits?
The Book of Enoch, which is Jewish pseudepigrapha and not Scripture, makes this claim, presumably about Genesis 6:
8 And now, the giants, who are produced from the spirits and flesh, shall be called evil spirits upon 9 the earth, and on the earth shall be their dwelling. Evil spirits have proceeded from their bodies; because they are born from men and from the holy Watchers is their beginning and primal origin; 10 they shall be evil spirits on earth, and evil spirits shall they be called. [As for the spirits of heaven, in heaven shall be their dwelling, but as for the spirits of the earth which were born upon the earth, on the earth shall be their dwelling.] 11 And the spirits of the giants afflict, oppress, destroy, attack, do battle, and work destruction on the earth, and cause trouble: they take no food, but nevertheless 12 hunger and thirst, and cause offenses. And these spirits shall rise up against the children of men and against the women, because they have proceeded from them. [1Enoch 15:8-12]
Clearly, the writer of 1Enoch 15:8-12 exalts his point of view above that of the Scriptures, which claim the demons are dead men (Deuteronomy 32:17; Psalm 106:36-37; cf. Isaiah 26:13-14).
Another word used for demons in the Old Testament is saiyr (H8163), while it is predominantly used for goats and kids, it is used twice to point to demons. The first is found in Leviticus 17:7, where the context is that all Israelites must no longer sacrifice in the field or elsewhere, but, rather, bring their sacrifices to the Temple only. If they offered a sacrifice anywhere else but the Temple, they sacrificed to demons and would be cut off from Israel.
The second place where saiyr (H8163) is used for demons is found in 2Chronicles 11:15. There, Jeroboam, the first king of Israel, after the Lord divided the kingdom into the House of Judah and the House of Israel, appointed his own priests to preside over worship centers where he (Jeroboam) placed idols of devils (or demons, i.e. idols of goats) and idols of calves. Once more, the demon was nothing but an idol of stone or precious metal and represented dead men of ages past, whose memory men continually worshiped.
Perhaps the most significant malady with demons being understood to be living sentient malevolent spirits is the fact that nowhere in the New Testament do we find an apostolic method for exorcising them; neither is exorcism listed as a gift of the Sprit! If they really were troublesome, malevolent spirits that possessed men, shouldn’t consideration have been made for our battling them? Certainly, we have Jesus’ example in the Gospels, but how does the description of his work point to demons being living, sentient beings, especially given their history in the Old Testament Scriptures?
The facts seem clear that the Jews of the first century AD received their understanding of demons from Jewish writings that arose out of the Inter-Testament period—from literature like: 1Enoch, Jubilees, The Life of Adam and Eve and 2Enoch. It is thought by scholars that this Jewish literature was heavily influenced by Zoroastrianism, the religion of Babylon. Zoroastrianism contains a personified dualism between the forces of good and the forces of evil, but such a thing is not found in the Old Testament or the New. Rather, it was introduced in post-exilic Judaism between the Lord and his angels and Satan and his angels, This idea should be rejected out of hand by believers today, considering its source.