Gandalf: Truly a Wizard?

[EllethValatari]

Okay, so I was in humanities class, and my teacher refers to Gandalf as a "wizard who uses magic." I raised my hand to express my disagreement with my teacher, saying that Gandfalf was in the Maia group Istari, and his powers were provided to him by Illuvatar, just as Christ's disciples were given they power by God to perform miracles. My teacher disagrees; saying that Gandalf is just like Harry Potter; in that there is a force which can be used for evil or good. I try to compare the two books (now that Harry Potter has been introduced to the conversation), saying that in Middle Earth, there is a divine god who gives power to thoses in authority, and may allow them to use it for evil, because their evil actions ultimately follow his providencial plan. On the other hand, in Harry Potter, there is a force, like in Star Wars, and no divine being ruling over it (or anything) My teacher still disagrees. How can I show him what I mean?