Genesis 4:7 “If thou doest well, shalt thou not be accepted? and if thou doest not well, sin lieth at the door. And unto thee shall be his desire, and thou shalt rule over him.”
The very first use of the word “sin” in the Bible occurs in the above verse. The two first brothers – Cain and Abel – offered sacrifices to God, but only one of them was accepted by God. Cain’s sacrifice was rejected, and God referred to his offense as sin.
In the above verse, it is clear that Cain’s “sin” in offering the wrong type of sacrifice would have been forgiven if he changed his mind and brought a right sacrifice. If he refused – which he did – he would be judged for his transgression.
In the Old Testament, there are three words used for sin. Each of them has the idea in them that God has established some standards for mankind to follow. Sin is missing the mark of God’s standard and deviating from them. Ever since the fall of Adam and Eve in the Garden of Eden, every human is born with a sin nature that quickly manifests itself.
Even Albert Einstein recognized this corrupt nature within man when he said, “The real problem is in the hearts and minds of men. It is not a problem of physics but of ethics. It is easier to denature plutonium than to denature the evil spirit of man.”
Human nature is bent toward breaking the standard set by God. All sin will be punished unless it is forgiven by placing your faith in Christ and seeking His forgiveness and making you a new person – one that desires to follow and obey Him. He died in your place so that you could be pardoned. You cannot cleanse your own heart from sin by any means.
When a person is forgiven and saved, God erases their sin from His books. He places a new nature within that individual and makes them His child. However, the sin nature is still there, but God wants to help him or her learn to overcome the old nature and get a victory that honors Him.