How did the snake convince Chavah to contravene Hashem's command, bearing in mind His warning that they would die if they did?
Rashi #1: The snake pushed Chavah 1 against the tree, and pointed out that just as she did not die after touching it, so too, would she not die after eating from it 2 (and he did this following Chavah's statement that Hashem had commanded them not to touch the tree - even though it was not true - Rashi in Sanhedrin 29a). 3
Rashi #2, Seforno (in Pasuk 5) and Targum Yonasan: He actually spoke Lashon ha'Ra (Motzi-Shem-Ra) 4 , by claiming that they would not die, and that Hashem threatened them with death because 'every craftsman hates his rivals' 5 - meaning that Hashem became all-powerful after eating from the Eitz ha'Da'as, and He did not want Adam and Chavah to become His rivals. 6
Gur Aryeh: Otherwise, what proof would the snake have to his assertion? Why would Chavah believe him?
Many people believe that if Hashem does not strike them down immediately after sinning, it means that they have gotten away with it (because either Hashem does not know or He does not care). As Seforno explained (to 3:1), it is the way of the Yeitzer ha'Ra to create fantasies, to make people believe what is not really true.
This gave the snake the opportunity that he wanted, and he said to her that, just as she did not die by touching the tree, so too, would she not die by eating it. The Midrash Rabah in Bamidbar 19:2 explains that the snake is found between fences, since it breached the fence of the world - it succeeded in enticing Chavah to eat only after it made her breach the fence not to touch (Divrei Eliyahu on Bereishis 3:3).
As we see in the following Pasuk.
This is nothing short of blasphemy, since it denies that Hashem preceded the world and created it (including the Tree), besides ascribing human shortcomings (jealousy) to Hashem (Kevayachol). In fact, he was telling her to believe in evolution, since there was no Creator! Oznayim la?Torah (in Pasuk #5): And the fact that Adam and Chavah believed the Nachash was their first sin, not eating from the Eitz ha?Da?as.
QUESTIONS ON RASHI
Rashi writes: "The snake said to her, 'Just as there is no death in touching [the tree], there is no death in eating from it either??. What was the snake's proof? Hashem had said, "On the day that you eat it, you shall die" (2:17); and the day was not over yet?
Moshav Zekenim and Chizkuni: The snake told her that she had nothing to lose by eating, since she was already liable for touching.
Riva: Chavah did not refer to 2:17. She thought that death would come immediately, saying simply, "lest you die" (3:3).
Gur Aryeh: Chavah thought the tree was naturally lethal, and she expected to feel some sort of pain immediately upon having touched it. Refer to 3:3:1:1.
Rashi writes: "The snake said to her, 'Just as there is no death in touching [the tree]...'" What is the snake's proof? Perhaps she did not die because she touched the tree unwillingly [for the snake had pushed her], whereas she might yet die for eating the fruit willfully?
Gur Aryeh: Chavah thought the tree was naturally lethal, and it was therefore irrelevant whether she touched the tree willingly or under duress. Refer to 3:3:1:1.
