國有難，回必亂 [国－难－－－乱]

Jyutping gwok3 jau5 naan4 ， wui4 bit1 lyun6
Pinyin guó yǒu nàn ， huí bì luàn

Definitions (Wiktionary)
  1. proverb
    Whenever the country (China) is in peril, the Hui people revolt.