Now the serpent was the most cunning of all the animals that the LORD God had made. The serpent asked the woman, 'Did God really tell you not to eat from any of the trees in the garden? The woman answered the serpent: "We may eat of the fruit of the trees in the garden; it is only about the fruit of the tree in the middle of the garden that God said, 'You shall not eat it or even touch it, lest you die.'" But the serpent said to the woman: "You certainly will not die! No, God knows well that the moment you eat of it your eyes will be opened and you will be like gods who know what is good and what is bad." The woman saw that the tree was good for food, pleasing to the eyes, and desirable for gaining wisdom. So she took some of its fruit and ate it; and she also gave some to her husband, who was with her, and he ate it. Then the eyes of both of them were opened, and they realized that they were naked; so they sewed fig leaves together and made loincloths for themselves. (Genesis 3:1-7)The creation accounts are actually very rich in theology. They offer us, in some ways, a glimpse into eschatology which is different from the glimpses we get from the New Testament. They also relate to us, in a metaphorical and literary (or mythical) manner the story of the Fall of man from his original supernatural state into his present natural one.
Here is the story of the Fall as told in Genesis. It may have been retold as "God made man, blessed him in a supernatural state, and placed him in a paradise. Man could do anything he wanted, so long as he did not do one little ting: eat form the tree of knowledge. As soon as God left the paradise for His one-day vacation, man ate from the tree of knowledge. Man! What a screw-up." While this is important for our theology--we would need neither redemption nor a Redeemer had our race not originally fallen from grace--it is all to easy to miss the humor of this passage.
First, I would like to write a disclaimer about this joke from Genesis. It is subtle. So subtle, in fact, that the writer of Genesis had to give us a hint: a possible (and indeed common) translation of the word "cunning " in the first verse is "subtle." In some ways, though, I think that this subtlety is a part of the joke. The heavenly hosts, which are so far beyond us in intellect, probably got the joke immediately; it took me the better part of 25 years and at least 100 readings of this passage to get it, and yet somehow I thought myself clever when I first understood the joke. I'm sure that the heavenly host got a good laugh at that!
In any case, the joke may begin as follows. What did the Phoenicians, the Babylonians, and the Egyptians all have in common? Two things, really. First, they were the major powers of the Mediterranean world around the time when Genesis would have been written down. Second, every one of them had some kind of myth involving a dragon; in some of the myths (the Babylonian one especially) the dragon was directly involved with the creation of the world; in all of the myths, the dragon was a representative of evil and power. Moreover, in some of these myths (again, the Babylonian myth especially), men were created of the blood (or some other element of) the primordial dragon--and therefore could be considered wicked. In others, men were misled or tricked by the evil dragons in some way.
Now turn to the Genesis account. Eve is tricked into eating of the forbidden fruit by a serpent, and through Eve, Adam. Now, it is true that the serpent has a number of symbolic connotations: they are guardians (in this case, maybe the opposite of a guardian), they are poisonous (man eats of the tree of knowledge and loses the tree of life, and thus dies), they are vengeful and vindictive (thus, a good vehicle for the recently fallen devil to work his vengeful and vindictive mischief). And while we often translate "serpent" as "snake," there is another translation for serpent which is particularly applicable in the mythical context: dragons are a type of serpent.
Thus, Genesis is here telling a joke about--indeed, poking fun at--the creation myths of the other religions of the day. The Babylonians believed that the world was a dragon's corpse, and mankind was born of the dragon's blood--thus implying that mankind was evil, and needed to be governed by a powerful and tyrannical government (Babylon) which would punish the evils of humanity with its cruelty. Man was evil, because man was from the dragon's own heart. Genesis, on the other hand, is saying that man had the story all wrong. He was created from dirt, not blood, and thus was neither necessarily good nor necessarily bad, but was rather a thing in which the seeds of both good and evil could be planted. As for the dragons, well, Genesis tells us to be ware of them, even if they're just snakes after all. The use of the serpent is, in a sense, God's way of saying to man, perhaps with a wink and a grin, "Watch out for those dragons! They'll really lead you astray."