Name of a demon mentioned in the New Testament as chief of the demons (Matthew 12:24-27; Mark 3:22; Luke 11:15-18). When the Pharisees heard (of the cures performed by Jesus), they said: "This man doth not cast out demons but by Beelzebul, the prince of the demons"; whereupon Jesus answered: "If Satan casts out Satan, he is divided against himself; how then shall his kingdom stand? And if I by Beelzebul cast out demons, by whom do your sons cast them out? But if I cast out demons by the spirit of God, then the kingdom of God is come unto you." On another occasion Jesus said to his disciples: "If they have called the master of the house [that is, himself] Beelzebub, how much more (shall they so call) them of his household" [that is, the disciples] (Matthew 10:25). The name "Beelzebub," written also "Beelzebul," which occurs nowhere else in Jewish literature, is a variant form of "Baal Zebub," the god of Eḳron, whose oracle King Ahaziah consulted during his illness, provoking thereby the wrath of God (2 Kings 1:2-16); the name is commonly explained after the Septuagint and Josephus, "Ant." 9:2, § 1, as the "Lord of Flies" (see BAAL-ZEBUB). Plagues being often ascribed to the influence of flies (Exodus 23:28; Ecclesiastes 10:1; Pliny, "Historia Naturalis," 10:28,75; Pausanias," Description of Greece," 5:14,1; Aelian, "Natura Animalium," 5:17, 11:8; Usener, "Götternamen," p. 260), the god who dispelled flies (Apollo Apomyios) probably retained his popularity long after he had ceased to be an object of worship. In fact, the fly was regarded by the Jews in particular as more or less impure and demonic. "The evil spirit ["yeẓer ha-ra'"] lies like a fly at the doors of the human heart," says Rab, with reference to "the flies of death" in Ecclesiastes 10:1 (Ber. 61a and Targ. Yer. to the passage). "A fly, being an impure thing, was never seen in the slaughterhouse of the Temple" (Abot 5:8), nor did one cross the table of Elisha; which fact, according to Rab, gave proof to the Shunammite woman that he was "a holy man" (2 Kings 4:9; Ber. 10b). The devil in German folk-lore also appears in the shape of a fly (Simrock, "Deutsche Mythologie," 1874, pp. 95, 479).
Geiger ("Urschrift," p. 53) thinks that Baal Zebub, in his capacity as god of the hated Philistines, became the representative of the heathen power and consequently the arch-enemy, the foe par excellence, and therefore the name "Baal debaba" ("debaba" being the Aramaic form corresponding to Hebrew "Zebub") acquired the meaning of "hostility," the verb 
with the sense of "hostile action" being derived from it. But neither this opinion nor a similar one expressed by Döderlein and Storr, and revived in Riehm's "Realwörterbuch," seems acceptable, as "Beel debaba" is the ordinary Aramean word for "calumniator." (Brockelmann, "Lex Syriæ.")
What renders the name still more problematic is the form "Beelzebul," which the older manuscripts present, and which has given rise to a number of other conjectures, among them the following: (1)It has been suggested that the appellations Beelzebub and Baal Zebub are corrupt forms of what was originally "Baal Zebul" (Baal of the heavenly mansion, 
, Movers, in "Journal Asiatique," 1878, pp. 220-225), and afterward "Baal of the nether world." (2) The word "Zebul" (from "zebel," dung) is a cacophonic corruption of "Zebub," in order to give the name the meaning of "god of the dung." It is more likely that the name "Beelzebul" is a dialectic variation of "Beelzebub," as "Beliar" is of "Belial"; Jerome read and translated the name as "dominus muscarum" (lord of flies).