To understand the reality of sin, we must first understand the character of God.
Among all His qualities, God has revealed to His people that He is holy and righteous. He hates sin and sinners, and all kind of wickedness and abominations.
The knowledge of good and evil came to man from the perspective of Satan. Man acquired his own standard of good and evil. He did not understand, and much less liked, God’s standard of good and evil.
The history of ancient Israel gives us a glimpse into the way of God in regards of good and evil. God is good, and He also is love, and His goodness and love stem from His righteousness, His holiness, and His truth.
In contrast, man is not good. Man, humankind, is spiritually dead; he cannot approach God, because he is sinful, born in iniquity. Man deceives himself by changing the name of sin. For him, sin is not sin anymore. In his imagination, in the thoughts of his wicked heart, man sees himself as “not too bad”, “sick”, and “able to correct himself”. All these are just the lies he believed from Satan. Man learned to be self-righteous.
The reality is that man is lost, in bondage to sin. After the fall, the human race lost the relationship with God. God expelled the man out of his Garden, and prevented him from eating of the tree of life anymore. Man was left with a “deceitful and desperately wicked heart” (Jer. 17:9)
God did all these things because He was going to sent Christ to shed His blood to cleanse a people for Himself. The filthiness of sin was so grievous, that the only way it could be cleansed was by the blood of Christ.
Ancient Israel, the people chosen by God in the Old Covenant, (they are not the people of God anymore) were not different than the world today. God, before destroying them for their iniquity, warned them through Jeremiah:
“Behold, ye trust in lying words, that cannot profit. Will you steal, murder, and commit adultery, and swear falsely, and burn incense unto Baal, and walk after other gods whom ye know not; and come and stand before me in this house, which is called by my name, and say, We are delivered to do all these abominations?” Jer. 7:8-10
Self-righteous Hebrews were not much different than self-righteous Christians, and the rest of our present world. So, sin is still sin, and still “the wages of sin is death”.