Jewish magic is a reference to mystical Kabbalah practices where the Old testament is used in such a way to nullify or make void the grace-based teaching of the New Testament. A wizard who casts spells is someone with arguments that are so convincing that they cause others to reject Christ and grace and the gospel. Jacob and Daqq on this forum are examples of people who have been 'taken down' by these practices and are actively spreading Torah observance. Dispensational beliefs are also an example of this dark art where all mention of spiritual Israel is seen as the highest sin. John Darby was a wizard or sorcerer. Those Christians who adhere to his beliefs come under the power of his spells and rarely if ever break free. Ellen White is also an excellent example of a sorceress who used the OT Sabbath to defeat the NT gospel. Her followers number in the millions today.