Heresy of Peor
The heresy of Peor is an event related in the torah at Numbers 25:1-15. Back references to the event occur in Numbers 25:18 and 31:16, Deuteronomy 3.28, Joshua 22:17, Hosea 9:10; Psalm 106:28.
Biblical account
The preceeding story is that of Balaam, in which a prophet, Balaam, ascends the mountain of Pe‘or, and sacrifices to God at the top of it. Having finished sacrificing, Balaam views the Israelites on the plain below, and pronounces a blessing over them, prophecying their blessed nature and destruction of Moab. When the narrative focus returns to the point of view of the Israelites, the contrast between Balaam's opinion of them, and their actual behaviour, is distinctly noticable.
According to the torah, the Israelites, after spending a short time in the plain of Moab, begin to involve themselves with the Moabite women. Consequently, under the influence of Moabite culture, the Israelites begin whoring after the Moabite gods, and join themselves to Baal Peor (Hebrew בעל פעור Ba‘al Pə‘ôr), in the Septuagint Beelphegôr, a baal associated with Mount Pe‘or.
Yahweh orders Moses to hang the chiefs of the people before Yahweh to turn away Yahweh's anger. The scene then abruptly shifts from concerns about Moabites to those about Midianites. A man brings a Midianite woman into the camp in the sight of Moses, where the people are weeping. Phinehas, grandson of Aaron, thereupon rises up with a spear, follows the man into the chamber and thrusts the spear through both the man and woman, who evidently were performing some sort of act requiring them to be close enough for this to be possible. The plague, mentioned suddenly for the first time, is averted, though 24,000 have died. A war with Midian follows later.
Ba‘al Pe‘or
These, and the biblical back-references, are the only ancient records referring to Ba‘al Pe‘or. There is no way of knowing whether Ba‘al Pe‘or was identical with any other Baal, of which there were several, or was only a local god of Mount Pe‘or. Later commentators tend to suppose that this god might be identical with Chemosh who is called the god of Moab in other biblical texts, and sometimes imagine, for their own religious reasons, that the cult of Ba‘al Pe‘al was very licentious.
Talmudic traditions
If Pe‘or is connected to the Hebrew stem p‘r 'open', used both of mouth and bowels, it might mean 'opening' and so Ba‘al Pe‘or could mean 'Lord of the Opening'. This apparent meaning is probably the source of Talmudic traditions associating Ba‘al Pe‘or with exposure and excrement. The tractate Sanhedrin 64a attibutes to Rab through Rabbi Judah the story of a sick Gentile woman who vowed to worship every idol in the world if she recovered. Upon recovery she set out to fulfill her vow, but drew back at Pe‘or as the rites were too disgusting: eating beets, drinking strong drink, and then uncovering oneself.
A story follows about a Jew who showed his contempt for the god by wiping his behind on its nose after defecating in the temple and who was praised for his piety by the acolytes of the god who said: no man has ever before served this idol thus. Tractate ‘Abodah Zerah 3 states in the Gemara that the area before the idol Pe‘or was used as a latrine and that the worship of the idol consisted of excrementing before it. Rashi comments on Numbers 25.3 that Pe‘or was so called because they would uncover before it the end of the rectum and bring forth excrement; this is its worship.
Such negative interpretations are most likely the result of a combination of folk etymology, and religious prejudice. One would expect rites as disgusting as these to gain wide notoriety, and consequently to be criticised by non-Jewish sources, of which there should be several survivals, though there are none.
Balaam
The story of Balaam may provide a clue concerning the identity of Baal Peor. Balaam is described as a ppProphet]] of El, usually translated as God. This is one of the first times that El is used, rather than Yahweh, in a biblical passage after the tale of the burning bush. While both are used to refer to Yahweh, El can also simply mean a god. While Balaam is described as a son of Beor, Beor is never himself identified, and the close phonetic similarity to Peor is noticable. If Beor and Peor are one and the same, then son of Beor merely identifies Balaam as being a prophet of Baal Peor.
Balaam is described as building altars at several of the high places of Moab, including at Peor, without ever criticising any Moabite religion occurring at those locations, entirely plausible if Balaam was a prophet of a Moabite god. Indeed, Balaam's own name is generally considered, in critical scholarship, to be a compound of Baal and Am, a semitic God. Later in the bible, within the account of the war against the Midianites, Balaam is described as being amongst those killed for committing the heresy of Peor, implying that Balaam was one of those who had joined themselves to Baal Peor.
An archaelogical find from 1967, from Deir Alla, in Jordan, produced an ancient Aramaic inscription written in red and black ink on plaster walls, telling about a hitherto unknown prophecy from a Book of Balaam, foretelling destruction for disobedience to the gods. Balaam, though still a son of Beor, in this narrative is a prophet of Shamash, the Semitic sun god. If this reflects the god that El refers to in the biblical text concerning Balaam, and the connection between Balaam and Baal Peor is accurate, then Baal Peor can be identified as Shamash.
From Moab to Midian
The abrupt change from concerns about the Moabites to the Midianites, and mention of the end of a plague which is never described as starting, is explained by the documentary hypothesis as being down to a change from the JE source to the Priestly source. Despite the torah redactor usually, according to the hypothesis, interlacing together the sources, the stories here were evidently difficult to combine, as the redactor appears to have cut the end of the JE version, and beginning of the Priestly source version, joining the remaining ends of each source together.
As the Priestly source is considered to be based on the JE source, albeit spun to the Aaronid priesthood's political viewpoint, the original JE ending, and priestly source beginning, can be expected to be fairly similar to the text that is currently present. Nethertheless, the use of plagues, by god, to punish the people in very large numbers, is unique to the Priestly source, once the Israelites have left Egypt, and consequently this detail is unlikely to have been present in the original.
While it is considered uncertain as to why the Priestly source would change Moab to Midian, it is generally agreed amongst critical scholars that the account of the war against Midian, and its spoils, originates from a writer who added these elements to the original version of the Priestly source. The command to vex the Midianites is also considered a part of these additions, and thus the revenge on Midian serves as a vehicle for this writer to include the list of spoils, and its distribution, which has a larger amount of text than the narrative of the war. Thus, this later writer could easily have changed Moab to Midian to facilitate this addition.