"Now the snake was the most clever of all the wild animals the Lord God made. One day the snake said to the woman,"Did God really say you must not eat fruit from any tree in the garden?"
The woman answered the snake, "We may eat fruit from the trees in the garden. But God told us, 'you nust not eat fruit from the tree that is in the middle of the garden. You must not even touch it, or you will die.'"
But the snake said to the woman, "You will not die. God knows that if you eat the fruit from that tree, you will learn about good and evil and you will be like God!" "
The woman, at this stage is doing as she should, listening to God, and not eating from the tree. She has even gone so far as to tell the snake what she has been told. The passage shows the snake to be deceitful, I think it is this description of the snake which promoted a lot of it's common 'characteristics' which are used throughout folklore and fiction. A more recent example being where J.K.Rowling used the snake as the emblem for the house of Slytherine who're supposed to be cunning and wily people.