The forbidden tree
It all started in the Garden of Eden... a place we can't imagine. No good and evil was known to them. Dead and pain didn't exist in the garden.
When eating of the fruits of the tree of knowledge of good and evil, Adam and Eve became conscious. Because of this they couldn't live in that garden anymore. They had the free will to choose and had chosen to rebel against God.
The tree of knowledge of good and evil was the beginning of sin and eventually dead because there was also another tree, the tree of life.
Adam was a body, soul and Holy Spirit being, when eating from the fruit they lost that Holy Spirit and became a dead spirit as all of us now. Jesus Christ came to die for our sins and rose on the third day as a promise to quicken that dead spirit and sent His Holy Spirit to all who believe and trust the Gospel of Paul. The only way to get back eternal life with God.
The tree of life probably provided eternal life to all in the garden but because they didn't obey God they were banished from the garden and condemned themselves with sin and death. So no more tree of life and death came to pass.
Using fig leaves wasn't enough to hide their shame and sin to God so He made them coats of skins. Animal sacrifice was in that time necessary to be forgiven of sins.
That forbidden tree was the beginning of rebellion of men. We are all the same, no exceptions, born as sinners because of Adam and Eve. Accept that, knowledge that and that's a start.
God loves us so much that He sent his own Son as the ultimate sacrifice to pay for our sins and welcome us in Heaven. Jesus Christ being God and sinless was amongst us to prepare His Kingdom and our home. No more animal sacrifice, no more laws but His Son Jesus Christ. He will return to judge us all by his Gospel. Be prepared.
For as in Adam all die, even so in Christ shall all be made alive.
1 Corinthians 15:22
And so it is written, The first man Adam was made a living soul, the last Adam was made a quickening spirit.
1 Corinthians 15:45
Nevertheless death reigned from Adam to Moses, even over them that had not sinned after the similitude of Adam's transgression, who is the figure of him that was to come.