Why did God have to explicitly tell Israel that murder was wrong when all other cultures had figured that out?

ROFL. Ah, Banana. If it hadn't been mentioned specifically, you'd be yammering on about how awful THAT was.

The nation of Israel has only existed since 1948.

I cannot find ANY reference to any communications between God and the State of Israel during this time.

Here are some interesting sections DEUTERONOMY 2:33-34 beneath God’s leadership, the Israelites totally destroyed the guys, ladies and youngsters of Sihon. "…we left no survivors." JOSHUA 10:10-27 God helped Joshua slaughter the Gibeonites. And there are a lot of others like that. So the real query will have to be, what type of shitty religion is this?

What was the purpose of the law that God gave to Israel?

As Paul tells us in Romans 3:19-20 God gave laws/rules to Israel (and therefore to all mankind) so that we could understand that we are not righteous. The purpose of the law was to let us all know that we are sinners who are in need of a Savior to pay for our sins. That Savior is God in form of a human being - Jesus.

That would be like "concluding" that we are slow even though it is on our books. Why should it be if we know it already?

Nevertheless, "For my people is foolish, they have not known me; they are sottish children, and they have none understanding: they are wise to do evil, but to do good they have no knowledge." Jer 4:22.

Deu 19:10 That INNOCENT BLOOD be not shed in thy land, which the LORD thy God giveth thee for an inheritance, and so blood be upon thee.

Well it's not that simple. God said murder was wrong, but Israel was confused about that because God ordered them to kill people all the time. They weren't sure what exactly God meant by "murder is wrong," since God's own orders went against his own commandments.

The Jewish people are mostly rich in America - so they're doing something right - I guess - I don't know

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