When Adam and Eve ate of the tree of the knowledge of good and evil the Lord said that they would die. The Bible says that the sin brings death. Man earned death when he sinned.
For the wages of sin is death, Romans 6:23a
The death that man experiences is first in his spirit. Man becomes separated from God spiritually. The spirit is what God made to commune with God. God is Spirit and those who know Him communicate in a spiritual way with God. They worship Him in spirit, they pray or talk with Him through their spirit and He speaks to them through their spirit. Man is the only spiritual creation that God made and separates man from the rest of all creation. When God made man in His image part of that was that God made man spiritual, to know Him and to be in a relationship with Him. That love relationship was lost when man sinned.
God is spirit, and those who worship Him must worship in spirit and truth.” John 4:24
The death that man next feels is the death to his soul. This death brings the shame of evil and the knowledge of the good that they have lost. One of the aspects of the meaning of good is the highest form of love and so when we sin then we lose experiencing and feeling love from the One whom we have sinned against. The relationship is no longer the same until it is restored. The love has been lost. God still loved man when he sinned but man no longer felt that love. It was lost to him. The soul is made up of the mind, will and emotions. Death to the soul brings the knowledge of the good thing that we had and we lost through our own foolish actions. It is that sick feeling of regret that we feel after we sin. Also, because we have sinned now our will has become a slave of sin and we sin again in the same manner even though with our mind we know it is not good.
Jesus answered them, “Truly, truly, I say to you, everyone who commits sin is the slave of sin. John 8:34
The last death that we will experience will be death to our body. This death is the destruction that we bring to ourselves through our sin. When we sin we lose the healthy love that we should have to take care of our own body. If Adam and Eve had not sinned then they would have never died. They would have been able to live forever in the presence of God and experienced the delight and joy of being in the garden with Him. We have all inherited the death that Adam brought to us when he sinned. Sickness and death is a part of the curse that came when man rebelled against God by not obeying Him.
Therefore, just as through one man sin entered into the world, and death through sin, and so death spread to all men, because all sinned— Romans 5:12
So, when man sinned he not only came into the knowledge of evil and lost his innocence and experienced shame but he also came into the knowledge of good. This knowledge of good is what revealed the darkness and sickness of sin and with it came great fear. The knowledge of good that man had now lost was the experiential knowledge of the love, the peace and the incredible joy and delight of a perfect relationship with God and the rest of creation. This knowledge of good brought the torment that one feels knowing what they have lost. One does not miss what one has never known. The knowledge of evil takes away the innocence of trust, of true love, of believing the best and of not fearing. Man lost everything pertaining to life when he ate of the tree of the knowledge of good and evil but most importantly he lost the delight of living in and experiencing God’s perfect love every second of every day. Adam and Eve also lost the perfect love that they had for each other and with it the trust and innocence in their marriage.
There is no fear in love; but perfect love casts out fear, I John 4:18a