… is from page book II, chapter 3 of G.H. von Berg’s Handbuch des teutschen Policeyrechtes  (1799-1804); I’ve not read this book, but found this quotation from it on page 193 of F.A. Hayek’s 1960 volume, The Constitution of Liberty :
How can there be a definite limit to the supreme power if an infinite general happiness, left to its judgment, is to be its aim? Are the princes to be the fathers of the people, however great be the danger that they will also become its despots?