What I am saying here is that God's law prohibits a very specific kind of killing. This type of killing did not happen even when the Israeli army was slaughtering unarmed, defenseless women and children. This type of killing would not have happened if Abraham really had killed his son. (An aside: This is very similar to your "1) Murder as a word means unlawful killing" "No, currently it means killing with intent, genius."!!! PS: It's still unlawful!)
If certain killings are permitted then what is an unlawful killing defined as? You seem to be missing the point that God has laws forbidding murder and then redefines what murder
is when it's useful to do so.
For example, every genocidal maniac in the world's history did not consider what they were doing murder, since they had some trumped up cause or another. We can, of course, condemn them as murderous. Yet God is magically immune to this kind of treatment! Anyway, a morality tangent is a bit pointless because Abrahamic Gods can all be easily demonstrated as immoral through sins of inaction. Onwards!
But anyway, what is an unlawful killing? No, seriously, answer the question. How is Abel's murder different from Abraham's son's ordered murder? Hint: God told one of them to do it, using a special Hebrew code word that makes it totally different from murder.
It doesn't magically stop being murder if you say it's not. I mean, I can't get away with that.
I'm at work so I can't refresh myself on Korah right now, but as far as Rahab is concerned there are two major schools of thought aside from "God's Law didn't apply to Rahab at the time because she was a filthy heathen"—which I personally don't hold. The first is that the commandment against false testimony suggests that Rahab even had she been an Israelite and subject to the 10 Commandments at the time of her lie, it would have been justified because she had no duty to tell the truth to the soldiers; similarly, you have no duty to tell armed intruders bent on raping and killing your wife and children specifically where they are hiding, and if telling a lie is more beneficial to them than keeping silent then you ought to tell the lie. I don't find this point of view very compelling.
First off they're stupid and/or dishonest:
Joshua 2:4-6 (New International Version)
But the woman had taken the two men and hidden them. She said, "Yes, the men came to me, but I did not know where they had come from. 5 At dusk, when it was time to close the city gate, the men left. I don't know which way they went. Go after them quickly. You may catch up with them." 6 (But she had taken them up to the roof and hidden them under the stalks of flax she had laid out on the roof.
That's straight up lying. And, again, notice the legalist tap dancing how God can exploit foreigners to do things his laws forbid because they're not part of the covenant. Also, the men wouldn't kill her if she wasn't hiding them in the first place!
What I subscribe to is that, similarly to my fireman example which you are so convinced is a strawman, she was rewarded for her confession of faith, not her being a liar and a prostitute.
New American Standard Bible (©1995); James 2:25
In the same way, was not Rahab the harlot also justified by works when she received the messengers and sent them out by another way?
So says James, anyway. I'd think he was an expert since he knew the guy.
That God and the Israelites spared her life (as they had promised!) and later accepted her into their society does not in any way imply an acceptance of all their acts.
Similar to how I can condemn a criminal (Rahab) and accept his stolen goods (Jericho) without being morally culpable or contradicting myself.
The Bible is full of characters (Noah, David, ...) who have faith in God AND obvious missteps for which they repent. Just because Noah is praised for his life and righteousness doesn't mean it's suddenly okay to get drunk all the time and flash your junk at your kids. Just because David is praised for his life and righteousness doesn't mean it's okay to send people to get killed to fuck their wives.
That's nice.
That we all fuck up and God forgives us even though there's no real reason to and we're just going to keep fucking up is kind of a core tenet of the Christian faith.
Pretty sure God makes worse mistakes and isn't really in a position to forgive anyone, but whatever.