The source of power for ALL classes and jobs is aether. The only important difference is if it uses external aether or just the internal aether of the practitioner. White and Black magic uses external aether. Conjury also, but to a limited extent. Just about every other case uses the internal aether or - in the case of crafter classes, aether from crystals.

So in short, paladins use their own internal aether to power their supernatural effects. You can call it magic if you wish, because magic is just ways of manipulating and controlling aether.