The Rectification is a neccessary bridge between Christianity and the ubermensch- a going over and a going down. Nietzsche prophesied a great noontide age that will welcome Zarathustra. The Rectification is a foundation stone of this great noontide, a rock upon which the peoples of that age may repose.
And once again shall ye have become friends unto me, and children of one hope: then will I be with you for the third time, to celebrate the great noontide with you.
And it is the great noontide, when man is in the middle of his course between animal and Superman, and celebrateth his advance to the evening as his highest hope: for it is the advance to a new morning.
At such time will the down-goer bless himself, that he should be an over-goer; and the sun of his knowledge will be at noontide.
Thus spoke Zarathustra, The Bestowing Virtue, 3