Among all his bad ideas, he had one that seemed promising to me, namely that it is the duty of every human being, to the extent of his capacity, to better themselves by striving to accomplish great things, even when it may entail sacrifice.
This sentence you write above is actually not compatible with the values promulgated by Nietzsche. He was staunchly non-egalitarian and would have rejected Jefferson’s statement that “all men are created equal.” Thus, the phrase “every human being” is something he would not have agreed with; rather, he believed that it was in the nature of the
stronger human being to overcome himself, to “overflow” with inner power. Though he believed this was indeed the “goal” of humanity, he never believed for a moment that all of humanity – or even the majority of humanity – was “worthy” of it in terms of having the requisite strength.
“Achievement” was also not a watchword of Nietzsche – certainly not worldly achievement. With Nietzsche, it was something more inward, more spiritual, although it did have outward manifestations. One proof of greatest strength was the ability to “yes” to life, to truly affirm life as it is (
amor fati, he called it, “love of fate”). He felt that Greek tragedy did this – what he called a “pessimism of strength.” Not to shy away from suffering but to affirm all of life, its joys as well as its sorrows. Everything else, in a sense, would follow therefrom, from this strength to say “yes” to life and to affirm reality in all of its joyousness
and all of its terribleness (like Oedipus, but who does not blind himself in despair over what he sees).
From such strength would come certain qualities – a “yes”-saying nature; a certain Dionysian joy, that could affirm life even in its suffering or most heart-breaking aspects; an overflowing generosity, “gift-giving virtue”, which has such an inner
wealth of spirit that it cannot help but “give away and distribute”, not in a material sense so much as a “spiritual” sense. Strength that showed a freedom from* ressentiment *(resentment); for Nietzsche, resentment and vengefulness, ill will, was a manifestation of weakness. Finally, Nietzsche eschewed pity; he preferred the “sharing of joy” to the “sharing of suffering” (to give a banal but pertinent example, Metallica’s song “Misery” has a very Nietzschean message in terms of critiquing a form of “compassion” that actually wallows in, multiples misery).
There is much in his philosophy that is compatible with Christianity,and an ambitious investigator could even try to draw parallels between Nietzsche’s “man of strength” and the personality of Christ, especially in the freedom from resentment and “gift-giving virtue” aspect of Nietzsche’s ideal. Nonetheless, it is true that
Nietzsche himself saw little similarity between his ideas, and those of Christianity. He saw Christ as a weak nature, not as a strong one. To disagree with him, though, does not mean that it is Nietzsche’s philosophy, in its entirety, that one has to reject. Where I think a Christian can affirm Nietzschean ideas is in an affirmation of strength and courage; self-mastery. Nietzsche also had critiques of Christians that Christians themselves could take to heart, in terms of self-criticism. Is it true that, for some Christians, turning the other cheek is a subtle of revenge? Taking the moral high ground can be a way of shaming one who has wronged you. (Nietzsche writes, “But if you have an enemy, do not requite him evil with good, for that would put him to shame. Rather prove that he did you some good”). Is there a difference between kindness out of genuine benevolence, and kindness out of sheer timidity or cowardice? Certainly there is; even Gandhi acknowledged as much (Nietzsche writes, "Of all evil I deem you capable: Therefore I want good from you. Verily, I have often laughed at the weaklings who thought themselves good because they had no claws.”) Nietzsche also critiques a certain
type of Christian when he writes, “The reverse side of Christian compassion for the suffering of one’s neighbor is a profound suspicion of all the joy of one’s neighbor, of his joy in all that he wants to do and can” (like Nurse Ratched from One Flew Over the Cuckoo’s Nest, the caregiver who is threatened at the prospect of her psych patient getting well and would prefer to keep him sick, as in her line, “what would your mother think?”). Nietzsche challenges Christians, by critiquing what he perceives to be less-than honorable psychological motivations, and some of these criticisms can indeed be of value to Christians themselves.