Googling can be fun. Entering the phrase "Man is free if he needs to obey no 
person" provided two links.  
 
The first link attributed the principle to 
"Christianity" [http://www.usagold.com/gildedopinion/Scott.html].   
 
The second link was a Lectures and Tutorials document of the University of 
Glascow School of Law 
[http://www.law.gla.ac.uk/Law/UploadedDocuments/Modules/8ZKV/2004/juris.doc] 
which attributed the quotation to Kant.  Perhaps we should start creating 
googlean stemmata. 
 
Nicholas J. Theocarakis