雷公打豆腐，揀軟的欺 [－－－－－－拣软－－]

Jyutping leoi4 gung1 daa2 dau6 fu6 , gaan2 jyun5 dik1 hei1
Pinyin léi gōng dǎ dòu fu , jiǎn ruǎn de qī

Definitions (CC-CEDICT)
  1. the God of Thunder strikes bean curd, a bully picks the weakest person
  2. to pick on an easy target