Selection from – Political Treatise - Chapter II, On Natural Right (Page 3)

Spinoza's Words – (man's free will results in actions which tend to preserve his existence)

Most people believe, that the human mind is produced by no natural causes, but created directly by God, and is so independent of other things, that it has an absolute power to determine itself... Experience, however, teaches us but too well, that it is no more in our power to have a sound mind, than a sound body.

Inasmuch as everything whatever, as far as in it lies, strives to preserve its own existence, we cannot at all doubt, that, were it as much in our power to live after the dictate of reason, as to be led by blind desire, all would be led by reason, and order their lives wisely; which is very far from being the case. For "Each is attracted by his own delight." Nor do priests remove this difficulty by deciding, that the cause of this is a vice or sin in human nature, derives its origin from our first parents' fall.

{Spinoza goes into detail of why Adam did not use reason and not disobey the commandment that caused his fall. Adam sucummed to his emotion as most men do.]

But that man, like other beings, as far as in him lies, strives to preserve his existence, no one can deny. For if any distinction could be conceived on this point, it must arise from man's having a free will. But the freer we conceived man to be, the more we should be forced to maintain, that he must of necessity preserve his existence.