Eating of the tree of knowledge represents using our own logic and reason to try to figure out and understand the Lord, something which is beyond us and which, ultimately, we have to simply accept. This was forbidden to the people at this stage of the Most Ancient Church because the Lord knew that if they did, they would lose their innocent acceptance of the Lord's love and leading, and would question it instead. This is represented by the idea that they would "die."

(References: Arcana Coelestia 198, 200, 201, 202, 203)

754. Having great anger.- That this signifies hatred against spiritual truths and goods, which are of faith and life from the Word, consequently against those who are in them, is plain from the signification of great anger as meaning, in reference to the devil, hatred. For anger, when said of the Lord, signifies zeal, within which there is nevertheless heaven, but when said in reference to the devil it denotes hatred, in which inwardly there is hell. That these and many other things are signified by anger and wrath may be seen above (n. 413, 481 at the end, 647, 693). The hatred of the devil is against spiritual truths and goods, because merely natural truths and goods are altogether opposite to these, for merely natural truths and goods are, in their essence, falsities and evils, although to those who are merely natural and sensual they appear to be truths and goods, because their goods are pleasures and delights springing from the loves of self and the world, and their truths are such as give countenance to those goods. And as the loves of self and the world are from hell, therefore, in their essence, they are evils and falsities. But spiritual truths and goods are in their essence truths and goods, because the goods are delights springing from love to the Lord, and from love towards the neighbour, and the truths are those which teach those goods; and as these truths and goods are from the Lord through heaven, therefore they are called spiritual, for everything which proceeds from the Lord is called spiritual. And since a man cannot receive these truths and goods unless he believes them and does them, it is therefore said, which are of faith and life from the Word. To live from the Word is to live from the Lord, for the Lord is in the Word, indeed He is the Word.

[2] Now because merely natural truths and goods, which in their essence are falsities and evils, are altogether opposite to spiritual truths and goods, which in their essence are truths and goods, therefore the devil, by whom hell is meant, is in unceasing hatred against them. This is why hatreds of various kinds continually ascend from the hells, while on the other hand, spiritual loves, also of various kinds, descend from the heavens; and between the hatreds of the hells and the loves of the heavens there is an equilibrium, in which men in the world are held, in order that they may be able to act from freedom according to reason. Those therefore, who do not live from the Word, but from the world, since they remain natural, receive evils and thus falsities from hell, and conceive from them hatred against spiritual truths and goods. Their hatred does not indeed appear in the world, because it lies concealed interiorly in their spirit, but it is manifested after death, when they become spirits. They then burn against those who are in spiritual truths and goods, with a hatred too great to be described; it is indeed a deadly hatred, for as soon as they see an angel who is in such truths and goods, in fact, if they only hear the Lord named, who is the source of these goods and truths, they immediately rush into passionate hatred, and feel nothing to be more delightful than to persecute them, and do evil to them; and because they are not able to destroy their bodies, they try with intense passion to destroy their souls.

[3] The reason why it is said, "Woe to those that inhabit the earth and the sea, for the devil is come down unto you having great anger," is that, after the Last Judgment, the state of the spiritual world was altogether changed. Before the Last Judgment those who were able to live a civil and moral life in externals, and yet were not spiritual, were allowed to form for themselves imaginary heavens, and there to enjoy pleasures like those in the world. But since the accomplishment of the Last Judgment this is no longer permitted, for now every one according to his life is carried away - he who is merely natural to hell, and he who is spiritual to heaven. This is the signification of the dragon and his angels being cast out of heaven unto the earth, namely, that previous to this they were permitted to have conjunction with the angels who were in the ultimate heavens, and in consequence of this to form for themselves such heavens, but now this is no longer permitted. This therefore is what is specifically meant by hatred against those who are in spiritual truths and goods; and such hatred is signified by the great anger which the devil has against those that inhabit the earth and the sea.