There are at least two possibilities: the woman may be protecting the tree against the assaults of the snake. By making the command even stronger, she makes it even clearer that the tree is not available, and there should be no more questions about it. But secondly, she may be so anxious to eat of that one tree that she makes the command stronger for her: why, we can't even touch that tree! In short, she wants that tree far more than the others and is waffling in the attempt to stay away from it. If she touches it, she fears she will surely eat. The latter reading seems to fit better with the subsequent actions of the woman.
The snake immediately retorts, "You will not die; for God knows that when you eat of it your eyes will be opened, and you will be like God (or 'you will be precisely God' or 'you will become like the gods'), knowing good and bad" (Gen. 3:4-5). The woman is mistaken, says the snake, in two important ways. First, her belief that death will be the result of eating of the forbidden tree is completely wrong. Rather than death, she will experience renewed life; the fruit of that tree will literally be an eye-opening experience. Second, the fruit of that tree holds the promise of divine knowledge; "you will be God" is one possible reading.
The woman falls silent, her eyes now fixed only on that one tree, now seen as the tree of enlightenment, the tree of divine knowledge. She now sees it as "good for food," a "delight to the eyes," and "to be desired to make one wise" (Gen. 3:6). She walks boldly to it, takes of its fruit and eats. But note—nothing yet happens. She then hands some to her man, who was with her, and he eats. While the woman dialogues with the snake, expresses her knowledge of God's command, her man just eats in silence. He is, it could be said, belly-oriented at best.
Then things start happening. "The eyes of both were opened (was the snake then right about the tree?), and they knew that they were naked . . ." It was indeed a tree of knowledge; they now "know" that they are naked. In Genesis 2:25, their nakedness was not a problem, but now it clearly is, for they scramble to solve the problem. "And they sewed fig leaves together and made loincloths for themselves." And thus the story ends in hilarious fashion, for ancient Hebrews knew all too well what fig leaves feel like; we might say something like number 2 grade sandpaper! When this grand tale was spun around campfires and in homes, all broke up laughing at this point. They sewed what together? Well, I bet those loincloths were scratchy indeed!
But of course that is the point of the story. When human beings think to become like God, they sew fig leaves together to cover their nakedness, because, as we ought to expect, God is all too right about us. We simply cannot eat of the tree of divine knowledge; it is far too dangerous for us human beings to do so. And whether our fig leaves are nuclear ones or fossil fuel ones or monetary ones, they remain scratchy fig leaves nonetheless.
God made us to serve and protect the great garden of God. But we would rather control and plunder and take over, forgetting that God is creator and sustainer of all of us and of all of the cosmos. And we stand, over and over again, scratching ourselves in our fig leaf aprons. Little wonder that we again this year need to go on a Lenten journey, searching for the light and leading of our God.