35. And they mingled with the nations and learned their deeds. 36. They worshipped their idols, which became a snare for them. 37. They slaughtered their sons and daughters to the demons. 38. They shed innocent blood, the blood of their sons and daughters whom they slaughtered to the idols of Canaan, and the land became polluted with the blood. 39. And they became unclean through their deeds, and they went astray with their acts.
Tehillim (Psalms), 106.35-39
17. They sacrificed to demons, which have no power, deities they did not know, new things that only recently came, which your forefathers did not fear.
Devarim (Deuteronomy), 32.17
Shedim (Hebrew: שֵׁדִים) are spirits or demons in Jewish mythology. However, they are not necessarily equivalent to the modern connotation of demons as evil entities. Evil spirits were thought as the cause of maladies; conceptually differing from the shedim, who are not evil demigods, but the foreign gods themselves. Shedim are just evil in the sense that they are not God.
They appear only twice (always plural) in the Tanakh, at Psalm 106:37 and Deuteronomy 32:17. Both times it deals with child or animal sacrifices. Although the word is traditionally derived from the root ŠWD (Hebrew: שוד shûd) that conveys the meaning of "acting with violence" or "laying waste," it was possibly a loan-word from Akkadian in which the word shedu referred to a spirit which could be either protective or malevolent. With the translation of Hebrew texts into Greek, under influence of Zoroastrian dualism, shedim were translated into daimonia with implicit negativity. Otherwise, later in Judeo-Islamic culture, shedim became the Hebrew word for Jinn with a morally ambivalent attitude.
Another legend said that God had started making them, intending for them to be humans, but did not complete their creation because He was resting during the Sabbath. Even after the Sabbath, He left them how they were to show that when the Sabbath comes, all work must be viewed as complete.
In three ways they are like ministering angels: They have wings like ministering angels; and they fly from one end of the world to the other like ministering angels; and they know what will be in the future like ministering angels. And in three ways they are similar to humans: They eat and drink like humans; they multiply like humans; and they die like humans.
They can cause sickness and misfortune, follow the dead and fly around graves.
Supposedly, sinful people sacrificed their daughters to the shedim, but it is unclear if the sacrifice consisted in the murdering of the victims or in the sexual satisfaction of the demons.
There are many things that one is admonished not to do in order to avoid invoking the shedim, such as whistling or even saying the word "shedim". The 2nd and 3rd century mystic Judah ben Samuel of Regensburg wrote in his will and testament that one should not seal up windows completely because it traps shedim in the house.
Shedim can shapeshift and assume a human form. The Talmud tells of Asmodeus assuming King Solomon's form and ruling in his place for some time. However, he was never seen barefoot because he could not disguise his feet.
In the Zohar:
The Shekhinah hid Esther from Ahasuerus and gave him a Shedah [a she-devil] instead while she returned to Mordechai's arms. [...] This is why a man must speak with his wife before he mates with her, because she might have been exchanged with a female demon.
- The Complete Jewish Bible. Chabad.org.
- The Complete Jewish Bible. Chabad.org.
- Dorian Gieseler Greenbaum. The Daimon in Hellenistic Astrology: Origins and Influence. BRILL, 2015. ISBN 9789004306219. p. 127.
- Dorian Gieseler Greenbaum. The Daimon in Hellenistic Astrology: Origins and Influence. BRILL, 2015. ISBN 9789004306219. p. 128.
- Benjamin W. McCraw, Robert Arp. Philosophical Approaches to Demonology. Routledge, 2017. ISBN 978-1-315-46675-0. p. 9.
- W. Gunther Plaut, The Torah: A Modern Commentary (Union for Reform Judaism, 2005), p. 1403 online; Dan Burton and David Grandy, Magic, Mystery, and Science: The Occult in Western Civilization (Indiana University Press, 2003), p. 120 online.
- "Old Testament Hebrew Entry for Strong's #7700 - שֵׁד". BlueLetterBible.org. Retrieved 8 March 2019.
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- Encyclopedia of Spirits: The Ultimate Guide to the Magic of Fairies, Genies, Demons, Ghosts, Gods & Goddesses. Judika Illes. HarperCollins, Jan 2009. p. 902.
- The Encyclopedia of Demons and Demonology. Rosemary Guiley. Infobase Publishing, May 12, 2010. p. 21.
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- Altschuler, David (1740–1780). Metzudat Zion on Isaiah. Chapter 34:14.
- Maureen Bloom. Jewish Mysticism and Magic: An Anthropological Perspective. Routledge, 2007. ISBN 978-1-134-10329-4. p. 128.
- The Encyclopedia of Demons and Demonology. Rosemary Guiley. Infobase Publishing, May 12, 2010. p. 21
- Zohar. 3:76b-77a.
- Babylonian Talmud. pp. Chagigah 16a.
- Maureen Bloom Jewish Mysticism and Magic: An Anthropological Perspective Routledge 2007 ISBN 978-1-134-10329-4 page 128
- Raphael Patai Encyclopedia of Jewish Folklore and Traditions Routledge 2015 ISBN 978-1-317-47170-7
- Marc Carlson, Notes on a demonic pantheon
- Babylonian Talmud. pp. Gittin 68a.
- Zohar. pp. 3:276a.
- "שדה | Definition of שדה at Definify". definify.com. Retrieved 2021-10-18.
- Ben-Amos, Dan. "On Demons." In Creation and Re-creation in Jewish Thought: Festschrift in Honor of Joseph Dan on the Occasion of His Seventieth Birthday. Mohr Siebeck, 2005, pp. 27–38, limited preview online.
- Charles, R.H. The Apocalypse of Baruch, Translated from the Syriac. Originally published 1896, Book Tree edition 2006 online.
- Charles, R.H. The Apocrypha and Pseudepigrapha of the Old Testament, vol. 2: Pseudepigrapha. Originally published 1913, Apocryphile Press Edition 2004, p. 485 online and p. 497.
- Chajes, Jeffrey Howard. Between Worlds: Dybbuks, Exorcists, and Early Modern Judaism. University of Pennsylvania Press, 2003, pp. 11–13 online.
- Goldish, Matt. Spirit Possession in Judaism. Wayne State University Press, 2003, p. 356 online.
- Heiser, Michael S. 2015. The Unseen Realm: Recovering the Supernatural Worldview of the Bible. 
- Koén-Sarano, Matilda. King Solomon and the Golden Fish: Tales from the Sephardic Tradition. Translated by Reginetta Haboucha. Wayne State University Press, 2004. Limited preview online.
- Plaut, W. Gunther. The Torah: A Modern Commentary. Union for Reform Judaism, 2005, p. 1403 online.
- Walton, John H., and J. Harvey Walton. 2019. Demons and Spirits in Biblical Theology: Reading the Biblical Text in its Cultural and Literary Context.
- Elyonim veTachtonim. An on-line database of angels, demons, ghosts and monsters in the Bible and Babylonian Talmud.