The idea is that there can be no peace without justice. You can have the appearance of peace, but silent injustice is just war with the mute button on. This means that peace requires more than passive acceptance of injustice and/or oppression. It requires the active elimination of both of these things everywhere and for everyone. This idea that you cannot have one without the other is why the phrase is sometimes written as: “No justice, no peace. Know justice, know peace.”

What @SavoirFaire said.