First Treatise: "'Good and Evil', 'Good and Bad'"

In the "First Treatise" Nietzsche aims to show that the valuations "good/evil" and "good/bad" have distinct origins and that the two senses of "good" reflect, in their origins, radically opposed meanings. The noble mode of valuation calls what it itself stands for "good", that is, everything which is powerful and life-asserting. In the "good/evil" distinction, which is the product of what Nietzsche calls "slave morality", so-called "evil" equates to what aristocratic morality calls "good". This valuation develops out of the ressentiment of the weak in the face of the powerful, by whom they are oppressed and whom they envy.
Nietzsche indicts the "English psychologists" for lacking historical sense. They seek to do moral genealogy by explaining altruism in terms of the utility of altruistic actions, which is subsequently forgotten as such actions become the norm. But the judgment "good", according to Nietzsche, originates not with the beneficiaries of altruistic actions. Rather, the good themselves (the powerful) coined the term "good". Further, Nietzsche sees it as psychologically absurd to suggest that altruism derives from a utility that is forgotten: if it is useful, what is the incentive to forget it? Rather such a value-judgment gains currency by being increasingly burned into the consciousness.
From the aristocratic mode of valuation another mode of valuation branches off which develops into its opposite: the priestly mode of valuation. Nietzsche suggests that a confrontation between the priestly caste and the warrior caste encourages this process. The priests, and all those who feel disenfranchised and powerless in a situation of subjugation and physical impotence (e.g., slavery), develop a deep and venomous hatred for the powerful. Thus originates what Nietzsche calls the "slave revolt in morality", which, according to him, begins with Judaism (§7), for it is the bridge that led to the slave revolt of Christian morality by the alienated, oppressed masses of the Roman Empire (a dominant theme in The Antichrist, written the following year).
Slave morality in feeling ressentiment does not seek redress for its grievances by taking revenge through action, as the noble would, but by setting up an imaginary revenge. It therefore needs enemies in order to sustain itself, unlike noble morality, which hardly takes enemies seriously and forgets about them instantly having dealt with them. The weak deceive themselves into thinking that the meek are blessed and will win everlasting life, thereby ultimately vanquishing the strong. They invent the term "evil" to apply to the strong and to that which proceeds from strength, which is precisely what is "good" according to the noble, aristocratic valuation. By contrast, the noble call their inferiors "bad"—in the sense of "worthless" and "ill-born" (as in the Greek words κακος and δειλος)—not "evil".
In the First Treatise, Nietzsche introduces one of his most controversial images, the "blond beast". He had previously employed this expression to represent the lion, an image that is central to his philosophy and made its first appearance in Thus Spoke Zarathustra.
Nietzsche expressly insists that it is a mistake to hold beasts of prey to be "evil", for their actions stem from their inherent strength, rather than any malicious intent. One should not blame them for their "thirst for enemies and resistances and triumphs" (§13). Similarly, it is a mistake to resent the strong for their actions, because, according to Nietzsche, there is no metaphysical subject. Only the weak need the illusion of the subject (or soul) to hold their actions together as a unity. But they have no right "to make the bird of prey accountable for being a bird of prey".
Nietzsche concludes the First Treatise by elaborating that the two opposing valuations "good/bad" and "good/evil" have been locked in a tremendous struggle for thousands of years, a struggle that originated with the war between Rome (good/bad) and Judea (good/evil). What began with Judea, Nietzsche sees as the triumph of ressentiment; for a moment in history, its hold was broken by the Renaissance, but it was reasserted by the Reformation (which, in Nietzsche's view, restored the Church), and refreshed again by the French Revolution (in which the "ressentiment instincts of the rabble" triumphed).
The First Treatise concludes with a brief section (§17) stating his own allegiance to the good/bad system of evaluation, followed by a note calling for further examination of the history of moral concepts and the hierarchy of values.