LEV750 "You must not practice divination nor soothsaying" [this verse]. ["You must not practice divination" – such as those who divine through weasels and birds. [Another example:] his bread fell from his mouth or a deer crossed his path, which [the diviner] then says is an omen that he will not be successful along his way, thereby causing him to turn away from it. Likewise, one should not turn to diviners, whether to do a certain deed or to refrain from doing one. "Nor soothsaying"--this derives from the root of the word referring to time periods and hours ["onah" is related to the word "t'onaynu.], whereby one says, "Today is an auspicious day for starting to work; this hour is inauspicious for going out." You should also not listen to what the astrologers have to say; rather, you must have faith in Hashem, the God of heaven and the God of earth. Therefore, the pasuk states regarding this (Devarim 18:13), "You shall be whole with Hashem"; [I.e., after the previous verses prohibit divination and soothsaying (Devarim 18:10), the pasuk says in contrast that one should have whole faith in Hashem.] this implies that diviners and soothsayers are wanting in their faith in Hashem. These immoral activities are "deeds of the Land of Canaan," as the pasuk continues (ibid. 14), "For these nations which you are taking over, listen to soothsayers and sorcerers. As for you, however, Hashem, your God, has not allowed you [to do] so."
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