How we cite our quotes:
I charge thee wait upon me whilst I live
To do whatever Faustus shall command,
Be it to make the moon drop from her sphere
Or the ocean to overwhelm the world.
I am a servant to great Lucifer
And may not follow thee without his leave.
No more than he commands must we perform. (1.3.34-40)
When Faustus calls Mephistopheles he's all about his expectation of commanding god-like power. But the response from Mephistopheles acts as a reality-check: all power has limits, even that of the spirits. This response should act as a warning to Faustus that what he desires is really out of his reach. He doesn't register that, though. He's too busy daydreaming about gold and far-off places.
Did not he charge thee to appear to me?
No, I came now hither of mine own accord.
Did not my conjuring speeches raise thee? Speak.
That was the cause, but yet, per accidens. (1.3.41-44)
Faustus thinks that something he has done caused Mephistopheles to appear. What Mephistopheles explains to him here is that his speech did cause him to appear, sure, but not because of Faustus's power. Mephistopheles appearance was just a side effect of Faustus's blasphemy. As Mephistopheles explains after this passage, devils always appear when someone rejects God, in the hopes of gaining that sinner's soul. In fact, Mephistopheles' appearance is as a master (Lucifer) hoping to win a slave—Faustus—and not the other way around, as Faustus believes.
Tell me what is that Lucifer, thy lord?
Arch-regent and commander of all spirits.
Was not Lucifer an angel once?
Yes, Faustus, and most dearly loved of God.
How comes it, then, that he is prince of devils?
O, by aspiring pride and insolence,
For which God threw him from the face of heaven. (1.3.60-66)
Are we supposed to believe that Faustus doesn't know who Lucifer is? What, has he been living under a rock? What happened to all that studying he was supposed to have been doing?