These lines are, for me, among the most powerful I've ever read:
[The pope-elect has been found on his little rock in the middle of a lake, where he exiled himself.]
"'Ah, holy lord," she sobbed, "I merit not your remembrance or your praise, for God knows my sin. When I protected you that day from the fisher's harsh words, he taxed me with wantonness and fleshly feeling for you and I denied the charge, falsely, as I now confess. For my eyes did really have to do with your limbs in the beggar's rags and with your noble features, and wantonness was at the bottom of the good I did you, depraved lost soul that I am!'
'That is a small matter," answered Gregorius, "and not worth talking about. Seldom is one wholly wrong in pointing out the sinful in the good, but God graciously looks at the good deed even though its root is in fleshliness. Absolvo te.' These were his words. It was the first instance of the extraordinary clemency he was to display as Pope, so consoling to all men and only offensive to the draconians."
There's nothing more important to me, to you, to any of us, than attaining this understanding. We all get it too late.
Of all the literature that I know, only Adalbert Stifter expresses this idea with more transparency, and yet, I have to admit that Mann's work has much greater scope than Stifter's. Mann's conception in this book and in others has the devil in it. (I'm not saying he's a satanist, but that his stuff is Faustian.) Stifter was much more careful. He had to be, in his careful age.
In Goethe, Novalis, Stifter, others, and here in Mann, this theme is treated in various ways-- our civilization is built on a natural foundation that is beyond good and evil, and sex is natural, and likewise beyond good and evil. That our values get their initial impulse from something as dubious as sex is something we all have to come to terms with.
The bible makes this point nicely too, but I don't know that book well enough to comment. German literature after Goethe seeks to reconcile the pantheistic focus on nature with Christian values. This process begins with Goethe's famous quote, ""In natural science, we are pantheists; in poetry, polytheists; morally, monotheists".