In chapter 10 of Goethe's Faust, Gretchen brushes off Faust. Faust wants Mephistopheles to help him, since Gretchen is above 14, but Mephistopheles declines. Then Faust says
Mein Herr Magister Lobesan,
Laß Er mich mit dem Gesetz in Frieden!
It seems that he calls Mephistopheles "Herr Magister Lobesan" and it may have something to do with law.
Who is "Herr Magister Lobesan" or what does it mean?