Sorry Mark, I did not see this earlier.
"Be proud of what German minds and German fists have accomplished. This ennobles you." or "Be proud of what German minds and German fists have accomplished as this ennobles you."
I try to put these things into English as it may have been said by an English speaker, so take your pick.
"Richtfest (this is an old tradition of consecrating, blessing, topping of a new structure which has just been completed)"
"Sperenberg-Heegesee ( Panoramio - Photo of Sperenberg - Heegesee )"
"Military Building Authority (or Army Building Office etc.) in Jueterbog"
Essentially you have a plaque here which was probably hanging during a ceremony (a Richtfest) which was held on the completion of a building put up in part or in whole by a military authority.
Here in the states this would be the sort of thing you might hang at a ribbon cutting ceremony.