Ge 3:1 Now the serpent was more cunning than any beast of the field which the LORD God had made. And he said to the woman, "Has God indeed said, 'You shall not eat of every tree of the garden'?"
2 And the woman said to the serpent, "We may eat the fruit of the trees of the garden;
3 "but of the fruit of the tree which is in the midst of the garden, God has said, 'You shall not eat it, nor shall you touch it, lest you die.'"
4 Then the serpent said to the woman, "You will not surely die.
5 "For God knows that in the day you eat of it your eyes will be opened, and you will be like God, knowing good and evil."
There are four things that Moses wants to teach here to his Israelite readers:
First, the serpent or the snake that the pagans worshiped during their time was in fact the one used by Satan in causing the Fall of Man. Snake worship is satanic.
Second, Satan often tempts us by making us believe that there are no dire consequences in disobeying God's Word. The denial of the judgment to come is satanic. God will surely and certainly punish Israel if they do not keep the Mosaic covenant.
Third, it is important to be established in the Word of God. Eve was not established in it and so she became an easy prey for Satan's temptations.
Israel should keep in mind Deuteronomy 4:2 which states: "You shall not add to the word which I command you, nor take from it, that you may keep the commandments of the LORD your God which I command you.
Fourth, Israel should learn that God's commandments are for their own good. His commandments are for their welfare. Satan would have them believe otherwise. He wants them to believe that God is withholding something good from them.
De 6:24 'And the LORD commanded us to observe all these statutes, to fear the LORD our God, for our good always, that He might preserve us alive, as it is this day.