system
Given the following post, respond as if you're commenting on Reddit:
human
How did Spinoza’s ideas about God challenge the views of orthodox theism?

I have read that Spinoza was (wrongly) called an atheist in his own time and was excommunicated from his Jewish community because of his views on God. I have also heard it said that the label of pantheism and the idea that he believed “Everything is God” isn’t really accurate either.

So I’m wondering:

1.) What did he actually believe about the nature of God.

2.) What problems did he have with the idea of God as proposed by Jews/Christians/Muslims.
gpt
Spinoza believed a lot of the “normal” things you’d expect about God. He thought he was a maximally great being, infinite in all ways, indivisible, necessarily existing, etc.

For a messy explanation, Spinoza explained things as substance (the thing) and it’s attributes that makes up its essence (how the thing is). So a triangle (substance) is a three sided shape (its essence). Spinoza argued that two substances can’t share the same essence. For example, a triangle and a ball can’t both be a three sided shape. If you’re a shape and got three sides, then you’re a triangle. 

Spinoza’s idea of God as infinite and lacking nothing, meant that he viewed God as a substance with infinite attributes. That is, he doesn’t lack any attributes. Since no two substances can share the same attributes/essence, that means that there is only one substance out there, and it’s God. That’s where the idea that “nature is God” with his thought comes from. All of reality is just God, and we see his infinite attributes manifested in the trees, people, stars, etc.

That’s already all heretical to Orthodox Judaism/Christianity/Islam. But Spinoza likely got in even hotter water because he openly denied the soul’s immortality, heaven and hell, that God punishes/rewards behavior, that prayer is anything other than superstition, that God has intention/goals/cares, etc. He also argued that the Bible was simply written by men, that the Law of Moses was never given by God, that Jesus was simply a moral teacher, etc.