Judaism & Dogs
Different Jewish views portray the animals as desired guards or evil demons.
Reprinted from The Jewish Religion: A Companion, published by Oxford University Press.
Rabbinic attitudes to dogs are somewhat ambiguous. On the one hand, it is permitted and even advisable to have guard dogs where there is danger of attack (a Midrash states that God gave Cain a dog to protect him in his wanderings) but, on the other hand, there are stern warnings against a Jew keeping a vicious dog in his house. The earliest reference to keeping dogs as pets is found in a German work of the 15th century, although, in the apocryphal Book of Tobit, it is said that the hero had a dog.
In the Kabbalah the dog is the symbol of the demonic powers. In a remarkable statement in the Zohar, evil in the universe can be compared to a vicious dog on a long lead. The dog seems to enjoy full, independent power to bark and harm but when there is a risk of it getting out of control the owner pulls it back in time. Influenced by the Kabbalah, Hasidic Jews never keep dogs as pets but many Orthodox Jews in Western lands see no objection whatsoever to this.