"Dont be a fool you fool"?

Question

Who said that and where did it come from?

Answer 1

I recall the line from a stanza in the middle of the song: "I'd Rather Be Blue Thinking of You (Than Be Happy with Somebody Else)"    The lyricist is Billy Rose, the second husband of f***y Brice.  Brice sang the song.  Barbara Streisand sings the song in "Funny Girl" as her encore after "The Rollerskate Rag."  Here is the verse with the line that you mentioned:

Will I be good? Will I be bad?

Don't be a fool, you fool

My little flat, I'm turning that

Into a Sunday school