It seems to me that Jacob faces two internal struggles throughout the book. One, with his religion. Two, with "lust;" also known as what is later his love for Wanda/Sarah. Basically, it's a battle between the two. Can it be described with one word? I'm trying to figure this out.
Jacob's religious struggle is fascinating to me. In my opinion, he is enslaved by religion more than anything else throughout the book. He practically starves himself when performing hard manual labor for the sake of eating kosher. He refuses to touch Wanda (most of the time) because she is not a Jew, nor are they married. The fact that he is circumcised is like Judaism's brand on him (although I have nothing against this practice, trust me). One of my favorite quotes relating to this issue is from page 123, "No matter what one does, one stumbles into sin." Jacob thinks this as he is leaving town on a wagon to return to Wanda, because he is embarrassing the widow he is standing up by not marrying. This quote basically describes organized religion to me. It's impossible to not sin! Everybody knows it. That makes being religious even harder, because the religious are constantly feeling guilty for sinning, and going out of their way to attempt not to sin, all the while knowing they're going to sin anyway. It's a stressful way of living, and Jacob definitely makes it seem that way.
On a related note, there is also a religious conflict among the Jews—to follow the laws scrupulously, or to be a good person? Another of my favorite quotes is about this, on page 247:
But now [Jacob] at least understood his religion: its essence was the relation between man and his fellows. Man's obligations toward God were easy to perform ... Rather than troubling himself to induce a Jew to eat pork or kindle a fire on the Sabbath, Satan did easier and more important work, advocating those sins deeply rooted in human nature.I like this passage because although I thought Jacob was devout to the point of craziness a lot of the time, this shows he was actually a good person. So many Jews in the book (Gershon is a prime example) picked and chose which laws they would follow scrupulously while completely disregarding others, which of course is disgustingly hypocritical.
Next, about Jacob's internal struggle with his lust/love. This basically ties in to his religious struggle because his religion is what dictates his every action and inaction. If that's not slavery, what is? I think I'm on to something here. In fact, Jacob even tells his cattle one time (page 90) "We are all slaves...God's slaves."
Anyway, Jacob initially denies Wanda because it's a sin for them to have sex or be involved in general. But when he does eventually give in, he makes Wanda immerse herself completely in a freezing cold stream so she'll be cleansed properly before they have sex. Preposterous! I admire her for putting up with this treatment, but then it actually sounded like it made things more exciting when they got down to it. Later, after Jacob is ransomed, his perpetual slavery is again addressed on page 113, "The Jews had ransomed him but he remained a slave. Passion held him like a dog on a leash." When I read the first sentence, I initially thought this was talking about how he is a slave to his religion, but apparently it's more about how he is a slave to passion/Wanda. I would argue that it could go either way. He is pretty passionate about his religion, more passionate than he is about Wanda. He loves Wanda, for sure, but he puts his religion above her in every situation. This, to me, is Jacob's worst downfall. Then again, I am not religious...I'm selfish. If I was Wanda, I would tell Jacob what's up, and I would not stand for that.
I fear that if I continue to write this will turn into more and more of a ramble, so I'll leave it with this. I think it's helped me figure things out a little.