The Torah commands in Parashat Kedoshim (Vayikra 19:26), “Ve’lo te’onenu,” which forbids determining when to act based on superstitious beliefs that certain times are more auspicious than others. It is forbidden to decide on the basis of these beliefs that performing a given task at one time will more likely yield the desired results than performing it at a different time. This command also includes practicing magic, even if it is done in a manner of “Ahizat Enayim” (illusions), deceiving people to make it appear as though one has supernatural, magical powers. The Sefer Ha’hinuch gives the example of a person who gives the appearance of pulling a snake out of his shirt, or who throws a ring into the air and then appears to take it out of somebody’s mouth. The reason behind this Misva, the Sefer Ha’hinuch explains, is because practicing magic could lead people to believe that some human beings have the power to overturn nature. This will then undermine their belief in Hashem, because they will assume that people are endowed with the same powers of He is, and they, like Him, can reverse the natural order. By forbidding magic, the Torah seeks to prevent people from mistakenly attributing supernatural powers to human beings, which would threaten their belief in the single Creator who exercises absolute control over the universe. This Misva applies in all places, in all times, and to both men and women. One who performs an action at a specific time on the basis of a superstitious belief in the auspicious nature of that particular time has transgressed this prohibition and is liable to Malkut. Inquiring as to the most auspicious time for this action does not violate the command of “Lo Te’onenu”; one transgresses this command only by acting upon such a belief. The Poskim address the question of whether modern-day magic shoes are forbidden by force of this command. Rav Moshe Feinstein (Russia-New York, 1895-1986), in Iggerot Moshe (Y.D., vol. 4, Siman 13), writes that since people nowadays realize that the magician has trained in the art of sleight of hand, and do not ascribe to him supernatural powers, today’s magic shows are allowed. He advises, however, that the magician make it clear from the outset that his magic is all illusions, and he does not actually practice magic.