The essence of sin

 For as by one man’s disobedience many were made sinners, so also by one Man’s obedience many will be made righteous. (Romans 5:19 NKJV)

 Adam and Eve’s first sin shows the essence of sin. They resisted God’s will and would not subordinate themselves to it, but rather chose to do what they felt was in their best interest. They wouldn’t let God decide what was best for them.

Instead of accepting that God was their Creator and as such they were subordinate to Him, they yielded to the temptation to put themselves in the place of God. God had said that if they ate of the tree, they would surely die. The serpent told them they wouldn’t. God had told them what was true, yet they disbelieved God’s word; they questioned who was right.

Prior to this first sin, Adam and Eve lived in harmony with their Creator. They enjoyed His fellowship; they trusted and believed Him. Their freewill decision to disobey God changed that, not just for themselves but for all of humanity.

Humankind stands guilty of sin before God due to Adam and Eve’s sin being imputed to all, and due to our own individual sinning. As sinners, we are separated from God.

God, in His love for humankind, made a way for humans to be forgiven, to be reconciled with Him, and to be spared from His wrath.

Being reconciled to God through Jesus, being forgiven for our sins, being redeemed, is the greatest gift one can receive—a personal gift directly from the hand of God. - Peter Amsterdam [1]

Sin may be defined as the personal act of turning away from God and His will. It is the transgression of God’s law … the violation of God’s command. It is the turning away from God’s expressed will. - J. Rodman Williams

[1] Anchor: Why Sin Matters