The events in the Garden of Eden illustrate mankind's present situation. In the garden God instructed man to eat of any tree except "the tree of the knowledge of good and evil" (Genesis 2:17). What does that mean? To symbolically "eat" from the tree meant to take to themselves, to have or presume to have. In other words, they were not to presume to have knowledge of what is good and what is evil. They were not to think that they knew right from wrong. They were not to decide for themselves what was right and what was wrong.
Why not? Why not let them decide? God alone is perfect and righteous, so God alone is qualified to determine right from wrong, good from evil. When Adam and Eve decided to "know" or determine good and evil, they were presumptuous: they presumed they could do what God alone could do. In essence - in this respect - they presumed to take God's place. God's response was "Behold, the man is become as one of us, to know good and evil: and now, lest he put forth his hand, and take of the tree of life, and eat, and live forever: Therefore the Lord God sent him forth from the garden of Eden, to till the ground from whence he was taken." (Genesis 3:22,23)
Perhaps you noticed the "us" in the quote above, implying God is plural. The same "us" appears in Genesis 1:26: "...let us make man in our image." Let me explain as briefly as possible. The "us" is the Father and the Word; the Word, through whom creation was done, later became flesh - the man Jesus - as related in John 1:1-3 and 14:
In the beginning was the Word, and the Word was with God, and the Word was God. The same was in the beginning with God. All things were made by him; and without him was not any thing made that was made... And the Word was made flesh, and dwelt among us, (and we beheld his glory, the glory as of the only begotten of the Father, full of grace and truth.
In a prayer Jesus confirmed His existence with the Father before creation:
And now, O Father, glorify thou me with thine own self with the glory which I had with thee before the world was. (John 17:5)
Jesus and the Father are of one mind, have one will and one plan. Jesus said:
I and [my] Father are one. (John 10:30)
Now, returning to the Garden of Eden: Adam and Eve were not alone. Satan was there with them:
Now the serpent was more subtil than any beast of the field which the Lord God had made. And he said unto the woman, Yea, hath God said, Ye shall not eat of every tree of the garden? And the woman said unto the serpent, We may eat of the fruit of the trees of the garden: But of the fruit of the tree which [is] in the midst of the garden, God hath said, Ye shall not eat of it, neither shall ye touch it, lest ye die. And the serpent said unto the woman, Ye shall not surely die: For God doth know that in the day ye eat thereof, then your eyes shall be opened, and ye shall be as gods, knowing good and evil. (Genesis 3:1-5)
Note that Satan lied when he said "ye shall not surely die." On the page God has a plan we'll see that Satan himself will die, in the future, as part of God's plan for removing evil. The Bible says "the wages of sin is death" (Romans 6:23) and Satan is no exception. The prophet Ezekiel wrote about Satan saying: "...thou shalt be a terror, and never shalt thou be any more" (Ezekiel 28:19).
Also note that Satan told them "ye shall be as gods, knowing good and evil" if they chose to "eat" from the tree - if they presumed to know good from evil. By violating God's instruction on what was right and wrong, Satan himself was presuming to know right from wrong. Satan was the leader in the revolt against God. Isaiah gives more insight into this, showing that Satan, apparently a long time in the past, had actually presumed to take God's place:
How art thou fallen from heaven, O Lucifer, son of the morning! [how] art thou cut down to the ground, which didst weaken the nations! For thou hast said in thine heart, I will ascend into heaven, I will exalt my throne above the stars of God: I will sit also upon the mount of the congregation, in the sides of the north: I will ascend above the heights of the clouds; I will be like the most High. Yet thou shalt be brought down to hell, to the sides of the pit. (Isaiah 14:12-15)
To eat from the tree of knowledge of good and evil means to reject God's instruction and then to "know" or decide on your own what is good and evil, right and wrong. To eat from that tree is to exercise total freedom of choice in our behavior, attitudes and beliefs rather than follow God's instruction. Today most of mankind has turned from God and chosen their own ways.
God has temporarily set us on our own, under Satan's influence, to let us experience the consequences of our own decisions. We are now free to exercise whatever political philosophies, government systems, social structures, utopian schemes, religious beliefs and so forth that we believe will work best for us. God knew that there would be no other fair, honest and convincing way to prove what was true and right. As events run their course we will ultimately bring ourselves to the brink of self-destruction. Then God will intervene, as described in God has a plan, and save us from self-destruction. He will show all mankind His ways in the ensuing Kingdom of God:
And he shall judge among the nations, and shall rebuke many people: and they shall beat their swords into plowshares, and their spears into pruninghooks: nation shall not lift up sword against nation, neither shall they learn war any more. (Isaiah 2:4)
Even while allowing us to experience the consequences of rejecting His instructions, God is exercising a plan of redemption and salvation. Ultimately, all who choose God's ways will be able to eat from "the tree of life" which was in the garden; they will enjoy eternal life with God as His sons and daughters, His family. In the Revelation this promise was confirmed:
He that hath an ear, let him hear what the Spirit saith unto the churches; To him that overcometh will I give to eat of the tree of life, which is in the midst of the paradise of God. (Jesus, in Revelation 2:7)
Blessed are they that do his commandments, that they may have right to the tree of life... (Revelation 22:14)