Insofar as man comports himself toward beings, he represents them with regard to the fact that they are, with regard to what they are and how they are, how they might be and how they ought to be-in short, he represents beings with regard to their Being. Such representing is thinking.
According to Nietzsche's statement, such representation has heretofore been determined by the spirit of revenge. Meanwhile human beings take their relationship with what is, a relationship that is determined in this fashion, to be the best possible sort of relationship.
In whatever way man may represent beings as such, he does so with a view to Being. By means of this view he advances always beyond beings-out beyond them and over to Being. The Greeks said this in the word μετά. Thus man's every relation to beings as such is inherently metaphysical. If Nietzsche understands revenge as the spirit that defines and sets the tone for man's relationship with Being, then he is from the outset thinking revenge metaphysically.
Here revenge is not merely a theme for morality, and redemption from revenge is not a task for moral education. Just as little are revenge and vengefulness objects of psychology. Nietzsche sees the essence and scope of revenge metaphysically. Yet what does revenge in general mean?
If at first we keep to the meaning of the word, although at the same time trying not to be myopic, we may be able to find a clue in it. Revenge, taking revenge, wreaking, urgere: these words mean to push, drive, herd, pursue, and persecute. In what sense is revenge persecution?* Revenge does not merely try to hunt something down, seize, and take possession of it. Nor does it only seek to slay what it persecutes. Vengeful persecution defies in advance that on which jt avenges itself. It defies its object by degrading it, in order to feel superior to what has been thus degraded; in this way it restores its own self-esteem, the only estimation that seems to count for it. For one who seeks vengeance is galled by the feeling that he has been thwarted and injured. During the years Nietzsche was composing his work Thus Spoke Zarathustra he jotted down the following observation: "I advise all martyrs to consider whether it wasn't vengeance that drove them to such extremes" (see the third Grossoktav edition, XII, 298).
* The clue may reside in the fact that the word here translated as "persecution," Nachstellen, is a morphological pendant to the word Vorstellen, "representation."