Full Idea
Frege claimed to have proved that the truths of arithmetic are analytic, but the logic capable of encompassing this reduction was logic inclusive of set theory.
Gist of Idea
Frege only managed to prove that arithmetic was analytic with a logic that included set-theory
Source
comment on Gottlob Frege (Grundlagen der Arithmetik (Foundations) [1884]) by Willard Quine - Philosophy of Logic Ch.5
Book Reference
Quine,Willard: 'Philosophy of Logic' [Prentice-Hall 1970], p.66