Messianic age

The phrase “Peace and righteousness (or justice)” is frequently shorthand for the eschatological or messianic age in both the OT—including Isaiah specifically—and in at least some Second Temple texts. Paul both knows this slogan and develops it, as Rom 5:1, 14:17, and several other texts make clear.

For Paul, then, Jesus is indeed the Prince of Peace, the one through whom God has made and is making the messianic shalom a reality, the covenant of shalom to which the scriptures of Israel bear witness.— The Death of the Messiah and the Birth of the New Covenant, page 160