ㄧㄤˇㄅㄧㄥㄑㄧㄢˋyǎngbīng‑qiānrìㄩㄥˋㄅㄧㄥˋˊyòngbīng‑yìshí

养兵千日,用兵一时
yǎngbīng‑qiānrì, yòngbīng‑yīshíㄧㄤˇ ㄅㄧㄥ ㄑㄧㄢ ㄖˋ,ㄩㄥˋ ㄅㄧㄥ ㄧ ㄕˊ
  1. 長期供養訓練軍隊一旦用兵打仗養兵千日,用兵一時」,今日正是各位報效國家時刻!」。

lit. Train an army for a thousand days to use it for an hour. (idiom)​; fig. extensive preparation eventually pays off