Who tells you hadda George. I swear in the book of mice and men?

The phrase "Hadda George" is not found in John Steinbeck's "Of Mice and Men."

It is possible you are misremembering the phrase, or perhaps you are thinking of a different book or work of literature.

Can you provide more context or information about where you might have heard this phrase? This could help me identify the source or understand what you are referring to.