Quote by Berthold Brecht from The Threepenny Opera. Said by both Macheath and Jenny in the ballad "Wovon lebt der Mensch".
It is kind of hard to translate into English, I'd simply say "First food, then morals". It expresses Brecht's insight that there are situations where one simply cannot afford to act morally. See also Maslow's Hierarchy of Needs.
This particular sentence has been quoted to death already (at least in German). Another common witticism by Brecht is:
"Was ist schon das Ausrauben einer Bank gegen die Gründung einer solchen!" (what's robbing a bank against founding one) - though that one is listed as not verified on wikiquote.
Update:
StrawberryFrog says a common translation is "Grub first, then ethics."
XWiz says the Pet Shop Boys put it as "Food is the first thing, morals follow on."
Update 2:
The ever helpful LEO translates it as "A hungry man has no conscience."