Being powerless, the slave can only resort to trickery to sabotage the master. With artful guile the slave introduces unnatural notions such as pity or compassion or feeling or caring in order to subvert the natural, healthy, dominating instincts of the strong. How clever of the sparrow to convince the hawk that it is evil to devour sparrows. How clever of the lamb to convince the lion that it is evil to consume the lamb. But in truth, no animal has conscience.
Conscience is an invention of the human slave.
Conscience is unnatural, the consequence of the slave's manipulation designed to immobilize the strong. Nietzsche writes of the genius of the Jews and Judaism. Jews were born slaves and they succeeded in changing the meaning of good and bad. The slave insists that human beings are to live according to God's nature, patient, compassionate, forgiving and loving. Judaism, Nietzsche maintained, is responsible for the cultural revolution that stems from the anger of impotence.