What does 死者は何も語らない mean?


As stated in the topic, what does 死者は何も語らない mean, maybe as an idiom? The
phrase is from a sentence in a novel, the speaker being a woman talking to a
girl. As a background, the girl is getting revenge on the woman, who killed
the girl's family and friends.

「…死者は何も語らぬ。妾も、貴様も、結局は私怨で、不条理な現実に対し自らが納得のいく結果を求めたに過ぎぬ。そんな妾と貴様の間に、どれ程の違いがあるというのだろうか、とな」




It's a quite literal equivalent to the English "Dead men tell no tales."

