מלכים ב י:ט פירוש: רש״י

“You are righteous.” In your eyes you are all righteous, and you consider me as being wicked because I killed the king. But look, now I revolted against my master and killed him. But who killed all these? I did not kill them. But from these you will know then that it is a decree of the King upon them, and whoever kills them is righteous and fulfills the commandment of the Omnipresent.