הֵ֥ן לְצֶ֖דֶק יִמְלָךְ־מֶ֑לֶךְ וּלְשָׂרִ֖ים לְמִשְׁפָּ֥ט יָשֹֽׂרוּ׃
Mit Gerechtigkeit wird der König regieren und die Fürsten nach Gebühr walten.
Rashi on Isaiah
Behold, for righteousness shall a king reign Behold a king has no right to reign except to execute righteous judgment.
Ibn Ezra on Isaiah
Behold a king shall reign, etc. This refers to Hezekiah and his princes, the firm establishment of whose government is promised.
Rashi on Isaiah
and over princes who rule with justice And over whom should he reign? Over princes who rule with justice. The prophet says this concerning Ahaz, who was a wicked man, but Hezekiah his son shall rule, and he is worthy. ([Manuscripts read:] And he is worthy of reigning.)