Jane Eyre is a convicting novel. If you have not yet read it, I would heartily recommend you do. Here is one particularly compelling passage asserting the importance and use of conviction.
“I care for myself. The more solitary, the more friendless, the more unsustained I am, the more I will respect myself. 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 the body and soul rise in mutiny against their rigour; stringent are they; involate 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 left at this hour to stand by: there I plant my foot.”