According to Nietzsche, master morality is a system created by pre-Christian warrior-aristocrats. It celebrates independence, excellence and the pursuit of power. It also encourages people to say "yes to life" by which they accept their inner desires and ambitions.
Conversely, slave morality arises from the oppressed class. It celebrates compassion, humility, and meakness. The values of master morality, such as power and dominance, are condemned as evil. In addition, slave morality encourages people to "say no" to themselves, by which people are told to control their natural impulses and practice restraint in following their inner desires.