I'm sorry right off the bat, because I have the need to say it seems you haven't really read the Bible. Possibly you have believed sound bites, Google glances, or partial truths?
> It's pretty clear that Jesus wanted everyone to follow Jewish law, just in a spiritual way and to actually mean it when they said they were doing those things out of devotion to God.
This is partially true. Jesus never disobeyed the Jewish law, and He did say it was still valid, but He also said He had fulfilled the Law, so people now were to follow Him. But you're right that what He was interested in was devotion to God based on a relationship, not a set of rules.
> But concepts like mercy, forgiveness, and "God is Love", and Jesus' proclamation that he who is without sin must cast the first stone, all of these are not in the Torah or the books of the prophets.
- Mercy: Ex. 33.19; Isa. 55.7, 63.9; Hosea 6.6, and many others
- Forgiveness: 2 Chronicles 7.14; Ps. 103.3; 130.4 and many others
- "He that is without sin must cast the first stone" is a reference to Deuteronomy 17.2-7. The Law stated that the witnesses of a crime, who brought it to the tribunal, should be the first to throw the stones of judgment. Jesus was showing that they were not really interested in the purposes of the law. They were using her as a pawn to trap him. Therefore the motives of her judges (the religious leaders), (possibly the husband), and the witnesses were not according to the Law, and Jesus has every right to challenge their attempt to secure the woman’s conviction. They were pure out hypocrites. If they were sinless, how had they qualified as witnesses, since this situation was clearly a set-up? Jesus's statement is grounded in the Law.
> Or the history of ancient Israel which is flecked with nightmarish violence, animal sacrifice, slavery, and the abuse of women. Kill 10,000 people with a donkey's jaw bone but if someone attacks you you must not fight back, and you must turn the other cheek.
You can't just toss out a half-dozen pet peeves like you're on a soapbox. I can only deal briefly with these misunderstandings.
- "nightmarish violence." It depends what you're talking about. It's tough to deal with generalities.
- "animal sacrifice." It was devotion to God, a very clear visual aid to theology. But the animals weren't just slaughtered and wasted. Animal sacrifice was how the people generally had meat to eat. From your reference, I'm presuming you didn't know this.
- "Slavery." This is a much longer topic. Basically it comes down to that slavery in the ancient world was not what we think when we think of slavery. We have Greece, Rome, and the colonial West to thank for the horrific abuses of slavery as a system and of people. In the ancient world, slavery was much more like our employment: it was debt slavery. When someone needed to pay their debts, they hired themselves out to someone else to earn the money. In the ancient world, someone else owned their labor, but not their person. It was an economic system, not a human abuse system. So much more to say here.
- "the abuse of women." It depends what you're talking about. The Bible isn't misogynistic, as many who just read it superficially presume. But if you're talking about other things, you need to specify. Like, some people think God commanded rape (He didn't.) Some people think He was OK with rape (He wasn't).
> Kill 10,000 people with a donkey's jaw bone but if someone attacks you you must not fight back, and you must turn the other cheek.
Um, some confusing seems to be afoot. Samson killed "1,000" people with a jawbone, but that number is symbolic, not literal. It's also possible it means "clansmen," not "1,000" (a grammatical thing).
And when Jesus said "turn the other cheek," he was not saying we can't or shouldn't defend ourselves. He was saying that we should take insult with rising to revenge. But this is a longer discussion. Suffice it to say, it seems that you have some misunderstandings.
> But it's hard to overlook the fact that a perfect deity would not be expected to change as radically between parts of "his" story in terms of their tone and personality. They're such different kinds of stories that it's impossible to believe the same violent, murderous God from the one is the peace-loving one in the other.
There was no change from God in the OT and God in the NT. In both He loves all, is willing and able to judge evil, to forgive the repentant, and to take anyone into relationship with Him who truly wants it. But I guess we'll have to talk further to straighten all this out. Let's talk.