ㄅㄨˋㄐㄧㄥˊˋbùjīng‑yíshìㄅㄨˋㄓㄤˇˊˋbùzhǎng‑yízhì

不经一事,不长一智
bùjīng‑yīshì, bùzhǎng‑yīzhìㄅㄨˋ ㄐㄧㄥ ㄧ ㄕˋ,ㄅㄨˋ ㄓㄤˇ ㄧ ㄓˋ
  1. 不經一番事件不能增長相關智慧 不經一事,不長一智事件教訓」。

You can't gain knowledge without practical experience (idiom)​; wisdom only comes with experience