This exact quote is not in Measure for Measure. However, I believe that the quote you are looking for is in this play. It really is practically the same quote, with one small change.
The quote you are looking for is in Act II, Scene 2 (I don't have line numbers, but it's about 2/3 of the way through the scene). It is spoken by Isabella to Angelo.
What she actually says (at least in the version of the play that MIT uses on their searchable Shakespeare site) is "man, proud man..."
But the quote is so close that it must be what you are looking for.