They have called "God" what was contrary to them and gave them pain; and verily, there was much of the heroic in their adoration. And they did not know how to love their god except by crucifying man.
As corpses they meant to live; in black they deck out their corpses; out of their speech, too, I still smell the bad odor of death chambers. And whoever lives near them lies near black ponds out of which an ominous frog sings its song with sweet melancholy. They would have to sing better songs for me to learn to have faith in their Redeemer: and his disciples would have to look more redeemed!
It is pretty clear that Nietzsche is not objecting to Christian hypocrisy, which is what he is usually quoted as having meant. He is working with his own definition of "redeemed". Redemption, for Nietzsche, means embracing life and the body, and their limitations, as all there is. It means not "hiding" in the promise of divine reward, punishment, or life beyond this one. Nietzsche mentions, in a few places, that Christians need redemption from their redeemer. This is what he is saying here. And when he says "They would have to sing better songs for me to learn to have faith in their Redeemer", he means the same: not that they need to sing better Christian songs, but that their songs are melancholy and they don't look redeemed precisely because they are Christian.
Thus Spoke Zarathustra Part II, "On Priests"