How we cite our quotes:
Hell hath no limits, nor is circumscribed
In one self place, but where we are is hell,
And where hell is, there must we ever be. (2.1.118-120)
Ever read Paradise Lost? In that piece, Satan declares, "Myself am hell." Like that declaration, Mephistopheles's description moves close to defining hell not as a place, but as a state of the soul. Those souls that are separated from God by their sins are in hell no matter what physical place they are in. It's everywhere.
But think'st thou heaven is such a glorious thing?
I tell thee, Faustus, it is not half so fair
As thou, or any man that breathe on earth.
How prov'st thou that?
'Twas made for man; then he's more excellent. (2.3.5-9)
Maybe we're missing something here, but why does it necessarily follow that heaven must be less beautiful than man just because it was made for him? This is probably an example of the twisted logic the devils often use to get a hold on Faustus's soul. Of course it totally works. See, Faustus? You should've stayed in school.
Now tell me who made the world?
I will not.
Sweet Mephistopheles, tell me.
Move me not, Faustus.
Villain, have I not bound thee to tell me anything?
Ay, that is not against our kingdom;
This is. Thou art damned; think thou of hell.
Think, Faustus, upon God that made the world. (2.3.66-74)
Why is the answer to Faustus's question so threatening to Mephistopheles? Maybe because the answer—that God made the world—is just too good. After all, if God made the world, then God must be awesome, and Mephistopheles only wants to talk about the bad stuff. Acknowledging the goodness of god would threaten Mephistopheles and Lucifer's hold upon Faustus's soul.