tiān xià xīng wáng, pǐ fū yǒu zé
天 下 兴 亡， 匹 夫 有 责

Everyone is responsible for the rise and fall of his country.

解释 ( paraphrase )
国家的兴盛或衰亡，每一个普通人都有责任来管。
这条谚语告诉我们：国家是众人的国家。每一个公民，应该关心国家的命运，为国家的名誉负起责任。

This proverb stresses that every citizen has the responsibility for caring about state affairs and his responsible for ups and downs of the country.

匹夫：泛指平常人。
         The common people.

造句 ( example )
正所谓“天下兴亡，匹夫有责”，现在正是国家困难的时候，我们怎能不伸出援手呢。