ㄐㄧˊㄈㄥㄐㄧㄥˋㄘㄠˇjífēng‑jìngcǎo

疾风劲草
  1. 猛烈大風才能知道怎樣堅韌比喻艱困危難才能考驗堅強意志節操 眾叛親離之後實在疾風勁草患難」。

the storm put strong grass to the test (idiom)​; fig. troubled times test a faithful minister, to show one's true colors after a stern test