1
general::
One will not do or say something. This disclaimer may be true or false, depending on the speaker or the context. For example, Far be it from him to disagree may be used as a straightforward indication that he is unlikely to disagree, or it may be used ironically to indicate that he actually disagrees quite strongly. [Late 1300s] For a phrase used similarly, see GOD FORBID.
American Heritage Idioms