"Resistance [Auflehnung] - that is the distinction [Vornehmheit] of the slave. Let your distinction be obedience. Let your commanding itself be obeying!"
[Thus Spake Zarathustra, Of War and Warriors.]

So the slave, if he has any nobility [Vornehmheit] in him, should rebel [auflehnen], not obey; whereas the warrior (who is of a higher caste than the slave) should obey, for in obeying he obeys himself (unlike the slave). As the slave fights for his own cause by rebelling, the warrior serves his own cause in obeying.