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general::
Phrase(s): Never make a threat you cannot carry out.
Prov. You should not threaten to do something you cannot do; otherwise, people will not believe you are serious when you threaten. • Bill: If you don’t stop being rude to me, I’ll have you fired! Jane: You’re not my boss. Never make a threat you cannot carry out.
McGrawhill's American Idioms And Phrasal Verbs