That was Adolf, reacting to my new shit
Translation: how come he can't be as evil as Lu get?
Well that's cause you ain't Lu, bitch

from Lupe Fiasco – SLR 2 Lyrics on Rap Genius

Meaning

Heil Führer Lupe!!

Adolf Hitler (Nazi Party, Holocaust, evil, etc.) doesn’t know how to handle Lupe’s evil lines (as you heard by the wackiness in the previous line). Hitler is actually jealous of Lupe’s evilness. Despite killing over six million Jews, he still wishes he could kill the rap game (like Lupe does). He can’t though, because Adolf Hitler is not Lupe Fiasco.

That german line refers to famous series of youtube videos entitled “Hitler reacts to…”, where incorrect (but funny) translations are added to the scene from The Downfall, where Hitler is… well he’s yelling at people.
https://www.youtube.com/watch?feature=player_embedded&v=SwoRg4d_tQg

This also could be a mockery of Kendricks Spanish lines on Collard Greens:

Hold up, biatch, this your favorite song
Translation: Ven aqui, mami, ese culo
Tu quiero coger mi huevos, y papi molestes pero
Chuparse puto pendejo, el pinche cabron

It’s also worth noting that in continuing with the German theme, Ernst Lubitsch (pronounced Lu-bitch) was a renowned German-American actor/film director. In his time, Lubitsch was known as Hollywood’s most elegant and sophisticated director — two terms that are often used to describe Lupe as an artist.

To help improve the meaning of these lyrics, visit “SLR 2” by Lupe Fiasco Lyrics and leave a comment on the lyrics box