Why Is the Dog Considered Impure?

Greetings and blessings.

With all due respect to the dog, and the Torah certainly holds it in esteem since, at the time of the Exodus when there was great destruction in Egypt, the dog did not bark at the Children of Israel. Because of this, it merits from the commandments of the Torah that the carcasses and forbidden animals are thrown to dogs, to show it appreciation. Nevertheless, the dog, being among the majority of animal species that neither chew the cud nor have split hooves, is forbidden to eat.

According to Kabbalah, only the kosher domestic animals and wild beasts are permissible to eat, since the sparks of holiness within them can be discerned by the person who eats with blessings before and after. This is not the case with impure foods, which undoubtedly also contain many sparks of holiness; nonetheless, the mixture of good and bad within them is a complete blend that human discernment cannot separate until the end of days.

See also the praise of the dog in the opening of the chapter "Song": "Rabbi Yeshaya, the disciple of Rabbi Hanina ben Dosa, fasted eighty-five fasts and said, 'Dogs are written about in the verse "and the dogs are mighty-spirited," they merit to recite this song: "Come, let us bow down, let us kneel, let us bless before Hashem, our Maker." A heavenly angel responded to him, saying: 'Yeshaya! How long will you fast over this decree which is from before Hashem? Since the day He revealed His secret to the prophet Habakkuk, He has not revealed this matter to any creature in the world except because you are the disciple of a great sage; therefore, they needed me from heaven, and they sent me to you and said: "Dogs are mentioned in the Torah, and to all the Children of Israel, not a dog shall bite its tongue." Not only that, but they merited to serve as leather for the writings of Shemot, the Torah, Tefillin, and Mezuzot..."'

Best wishes - Menashe Israel