From the Arbatel of Magick, Third Septenary, Seventeenth Aphorism:
Mediocribus Magis, mittunt de suis Spiritibus, qui in determinatis tantûm quibusdam negotiis illis obtemperent.
"To the Mediocre Magicians, they send their spirits to obey them in carrying out specific tasks." (My translation.)
Mediocribus can mean ordinary, normal, or average. I like "Mediocre," because it demonstrates something about magic that I tend to forget. For all the fun I have conjuring spirits and having them get me stuff and influence my world, that's just normal. For Magicians. It's to be expected.