Answer Happy

In his famous essay "the role of monetary policy" Milton Friedman says: "There is always a temporary trade-off between inflation and unemployment there is no permanent trade-off. The temporary trade-off comes not from inflation per se, but from unanticipated inflation, which generally means from a rising rate of inflation. The widespread belief that there is a permanent trade-off is a sophisticated version of the confusion between 'high and rising' that we call recognize in simpler forms. A rising rate of inflation may reduce unemployment, a high rate will not." Please explain this quote.