养兵千日,用兵一时 meaning in English

A thousand days the country nurtures its soldiers and all for one day's battle.Armies are to be maintained for years but used on a single day.Armies are to be maintained in the course of long years,but to be used in the nick of time.maintain soldiers a thousand days for one hour's serviceTroops are kept a thousand days to be used on one day.train troops for a thousand days and use them in an emergencyYou maintain troops for a thousand days,and use them only one day.