Taken from Stanford Encyclopedia of Philosophy
The world must, in some sense, be a part of "god," although god is not conceived in a traditional, monotheistic way (old man with beard): "“those who feign a God, like man, consisting of a body and a mind, and subject to passions. But how far they wander from the true knowledge of God, is sufficiently established by what has already been demonstrated.”
"This proof that God—an infinite, necessary and uncaused, indivisible being—is the only substance of the universe proceeds in three simple steps. First, establish that no two substances can share an attribute or essence (Ip5). Then, prove that there is a substance with infinite attributes (i.e., God) (Ip11). It follows, in conclusion, that the existence of that infinite substance precludes the existence of any other substance. For if there were to be a second substance, it would have to have some attribute or essence. But since God has all possible attributes, then the attribute to be possessed by this second substance would be one of the attributes already possessed by God. But it has already been established that no two substances can have the same attribute. Therefore, there can be, besides God, no such second substance."
We see "things" in nature as serving ends, often our ends. But Spinoza says this is an anthropomorphizing fiction:
"Spinoza's fundamental insight in Book One is that Nature is an indivisible, uncaused, substantial whole—in fact, it is the only substantial whole. Outside of Nature, there is nothing, and everything that exists is a part of Nature and is brought into being by Nature with a deterministic necessity. This unified, unique, productive, necessary being just is what is meant by ‘God’. Because of the necessity inherent in Nature, there is no teleology in the universe. Nature does not act for any ends, and things do not exist for any set purposes. There are no “final causes” (to use the common Aristotelian phrase). God does not “do” things for the sake of anything else. The order of things just follows from God's essences with an inviolable determinism. All talk of God's purposes, intentions, goals, preferences or aims is just an anthropomorphizing fiction."
Spinoza does not worship nature, but rather promotes rational knowledge as a way to gain an intellectual acceptance of things, and all things being necessary, it is the task of man to learn to tame the passions.
"We do not have an absolute power to adapt things outside us to our use. Nevertheless, we shall bear calmly those things that happen to us contrary to what the principle of our advantage demands, if we are conscious that we have done our duty, that the power we have could not have extended itself to the point where we could have avoided those things, and that we are a part of the whole of nature, whose order we follow. If we understand this clearly and distinctly, that part of us which is defined by understanding, i.e., the better part of us, will be entirely satisfied with this, and will strive to persevere in that satisfaction. For insofar as we understand, we can want nothing except what is necessary, nor absolutely be satisfied with anything except what is true."