抱打不平

Explanation: Meet unfair thing, to come forward to help victims of bullying side. 　　Source: Qing Cao Xueqin's "Dream of Red Mansions" Forty-fifth back: "I only have gas for the children something for peace. 　　Examples: Upon my honor, said the two, the old man his life, the most like robbing the poor associate professor of the strong and the weak ~. (Qing Zeng Pu, "Flower" thirty-fifth back)