哀兵必胜

āi bīng bì shèng suǒ yǐ lì jīng mó nàn de tā men yī dìng néng chéng gōng

哀兵必胜，所以历经磨难的他们一定能成功。

As an army under heavy pressure and burning with indignation is sure to win, they who have experienced so much are sure to win.