Genesis 2:16-17 The tree of knowledge

          The tree of the knowledge of good and evil and the tree of life

¹⁶ And the Lord God commanded the man, saying, Of every tree of the garden thou mayest freely eat: ¹⁷ But of the tree of the knowledge of good and evil, thou shalt not eat of it: for in the day that thou eatest thereof thou shalt surely die. -Genesis 2:16-17 King James Version (KJV)

At this stage in our Eternal Journey mankind used to partake of the fruit of Eternal Life or in other words we did not have to suffer death as we experience it today. This represents the "Fall of man" when millions of years ago we turned from the Light and fell from the Presence of God.

 Arcana Coelestia, by Emanuel Swedenborg, [1749-56], tr. by John F. Potts [1905-10], at sacred-texts.com
 

125. Verse 16. And Jehovah God commanded the man, saying, Of every tree of the garden, eating thou mayest eat. To "eat of every tree" is to know from perception what is good and true; for, as before observed, a "tree" signifies perception. The men of the Most Ancient Church had the knowledges of true faith by means of revelations, for they conversed with the Lord and with angels, and were also instructed by visions and dreams, which were most delightful and paradisal to them. They had from the Lord continual perception, so that when they reflected on what was treasured up in the memory they instantly perceived whether it was true and good, insomuch that when anything false presented itself, they not only avoided it but even regarded it with horror: such also is the state of the angels. In place of this perception of the Most Ancient Church, however, there afterwards succeeded the knowledge of what is true and good from what had been previously revealed, and afterwards from what was revealed in the Word.
126.

Verse 17. But of the tree of the knowledge of good and evil, thou shalt not eat of it; for in the day that thou eatest thereof, dying thou shalt die...
128.

The worldly... man says in his heart, If I am not instructed concerning the faith, and everything relating to it, by means of the things of sense, so that I may see, or by means of those of the memory, so that I may understand, I will not believe; and he confirms himself in this by the consideration that natural things cannot be contrary to spiritual. Thus he is desirous of being instructed from things of sense in what is celestial and Divine, which is as impossible as it is for a camel to go through the eye of a needle; for the more he desires to grow wise by such means, the more he blinds himself, till at length he believes nothing, not even that there is anything spiritual, or that there is eternal life. This comes from the principle which he assumes. And this is to "eat of the tree of the knowledge of good and evil" of which the more anyone eats, the more dead he becomes. But he who would be wise from the Lord, and not from the world, says in his heart that the Lord must be believed, that is, the things which the Lord has spoken in the Word, because they are truths; and according to this principle he regulates his thoughts. He confirms himself by things of reason, of knowledge, of the senses, and of nature, and those which are not confirmatory he casts aside.

129.

Everyone may know that man is governed by the principles he assumes, be they ever so false, and that all his knowledge and reasoning favor his principles; for innumerable considerations tending to support them present themselves to his mind, and thus he is confirmed in what is false. He therefore who assumes as a principle that nothing is to be believed until it is seen and understood, can never believe, because spiritual and celestial things cannot be seen with the eyes, or conceived by the imagination. But the true order is for man to be wise from the Lord, that is, from His Word, and then all things follow, and he is enlightened even in matters of reason and of memory-knowledge. For it is by no means forbidden to learn the sciences, since they are useful to his life and delightful; nor is he who is in faith prohibited from thinking and speaking as do the learned of the world; but it must be from this principle-to believe the Word of the Lord, and, so far as possible, confirm spiritual and celestial truths by natural truths, in terms familiar to the learned world. Thus his starting-point must be the Lord, and not himself; for the former is life, but the latter is death...