(9) When you enter the land that the LORD your God is giving you, you shall not learn to imitate the abhorrent practices of those nations. (10) Let no one be found among you who consigns his son or daughter to the fire, or who is an augur, a soothsayer, a diviner, a sorcerer, (11) one who casts spells, or one who consults ghosts or familiar spirits, or one who inquires of the dead.
(12) For anyone who does such things is abhorrent to the LORD, and it is because of these abhorrent things that the LORD your God is dispossessing them before you. (13) You must be wholehearted with the LORD your God. (14) Those nations that you are about to dispossess do indeed resort to soothsayers and augurs; to you, however, the LORD your God has not assigned the like.
Why does the Torah prohibit sorcery and fortune telling?
Rav went to a graveyard, and did what he did, i.e., he used an incantation to find out how those buried there died, and he said: Ninety-nine of these died by the evil eye, and only one died by entirely natural means.
Gemara relates: There was a certain woman who would try to take dust from beneath the feet of Rabbi Ḥanina in order to perform sorcery on him and harm him. Rabbi Ḥanina said to her: Take the dust, but the matter will be ineffective for you, as it is written: “There is none other beside Him.”