When people pray, they generally ask for something, and the requests can range from material objects, to forgiveness, or be a need of penance.
In this sense, praying, as well as self-sacrificing are expressions of neediness, rather than gratitude. It has an infantile and winning dimension. One forgets, that if one were really addressing divinity, let alone, communicating with "it", one would be in awe, not in want. Maybe that is why Nietzsche considers all religiosity a form of gratefulness, of which, I think, awe is the highest expression.
But asking God for "this" and "that", or mechanically repeating the words of a prayer out of religious "duty", makes people consider themselves righteous, even though they do nothing other than "negotiate" with divinity.
Sacrifice, in the same line, was some sort of negotiating with God, what is not only disrespectful, but contradictory.
In the same way that a real prayer should be an expression of reverence in addressing divinity, sacrifice, an ultimate and final prayer, should never be a transaction with the view to a return. Sacrifice is the extreme surrender of communing with God; become a an offer of oneself, to Him.
In love with the Father, Christ was a gift, not a victim.
The Christian sacrifice, usually understood as a purging of the world's sins by "the lamb of God", was Christ's terrible, painful and passionate return to his deepest Self, where the endless love between creator and creature resides; "the will of the father". That is why, even being critical of Christianity, Nietzsche saw the Christian sacrifice not as a trade off of Christ's life for the salvation of the world, but as a matter of authenticity to Christ.
As we all know, Christ was not exclusive in considering himself a son of God, but, on the contrary, considered all of us to be children of the Father, just like himself.
Christianity reawakened, through metaphor, a still more atavist religious practice, which is that of cannibalism. The immensity of such love, of being at one with the loved one, in flesh and blood, more than self-sufficient, is pure exuberance: it needs nothing, and it asks for nothing.
In the context of nature, the bond between life and death is constantly revealed. Animals are killed, so their predators can live on. Babies are born, out of lacerated bodies. The women, who were girls until giving birth, cease to exist when they become mothers. Seeds die, in order to bear fruit(and this is a cherished Proustian analogy).
Even if just metaphorically, resurrection, as an overcoming of oneself, follows sacrifice. Resurrection is not a "goal"to be attained, but a rebirth that is intrinsic to dying for God. Here, we come to Proust and his enlightened view of the several deaths of the selves that we were, throughout life.
When he loved Gilberte, he was a different person from the one he came to be, after arduously forgetting her, and eventually falling in love with Albertine. Death of that self, as an overcoming of it through suffering, gives birth to a new self; to a metaphorical resurrection.
We all know the saying "no pain, no gain". Proust says the same, when asserting that pleasure is good for the body, but only pain can strength the spirit. He expresses the dynamics of the Christian sacrifice/resurrection, when saying:
"Chaque personne qui nous fait souffrir peut-être rattachée par nous `a une divinité dont elle n'est q'un reflet fragmentaire et le dernier degrée, divinité dont la contemplation en tant qu'idée nous donne aussitôt de la joie, au lieu de la peine que nous avions. Tout l'art de vivre c'est de ne nous servir de personnes qui nous fount souffrir que comme d'un degré permettant d'aceder `a sa forme divine et de peupler ainsi journellement notre vie de divinités." (Each person who makes us suffer may be linked by us to a divinity of which he is only a fragmentary reflection and the last degree, a divinity whose contemplation as an idea immediately gives us joy, instead of the pain we had. The whole art of living is to use people who make us suffer only as a step allowing us to access our divine form and thus daily populate our life with divinities."
