Jane Eyre, Doctor of the Church...

...or at least a fine moral theologian.
This passage has come to me several times recently in reading arguments for adultery and mental illness against chastity. You know, it's mean to tell people that they ought not do or have what it is they want...

I will keep the law given by God; sanctioned by man. I will hold to the principles received by me when I was sane, and not mad—as I am now. Laws and principles are not for the times when there is no temptation: they are for such moments as this, when body and soul rise in mutiny against their rigour; stringent are they; inviolate they shall be. If at my individual convenience I might break them, what would be their worth? They have a worth—so I have always believed; and if I cannot believe it now, it is because I am insane—quite insane: with my veins running fire, and my heart beating faster than I can count its throbs. Preconceived opinions, foregone determinations, are all I have at this hour to stand by: there I plant my foot.

(Several of the more recent dramatizations of C B's masterwork have left me disgusted, Jane is seen to reject her married lover out of pride rather than a determination not to do evil, not to, quaint word, sin. Perhaps their creators simply do not believe in sin.)