What man among you has not looked on another woman with lust?
What man among you has not hated someone at one point?
What man among you has not put himself first over others?
What man among you has not loved himself more than God and served himself before God?

The law is a very powerful instrument. It shows a man his fallen nature. When a man truthfully looks inside his heart he sees his inability to uphold the law.

Men have the law written in their heart. Placed there by the creator to lead the to The Christ.

Men know right from wrong. Men choose to act for or against such spiritual laws. When a man willingly chooses to go against these, he commits sin. And all men commit sin because it in in their nature.

A man who says he upholds the law is a liar. A man who says he is without sin is a liar. He seeks to please God on his own. He does not come to The Christ for all his needs. He does not see his depravity and fallenness and sinful nature.

This man does not think he needs a propiation for his sin. He believe he can please God with his own merit. He think he can fulfill the law.

He looks to climb in through the window and not go in through the door.

The scripture is clear. Man cannot fulfill the law. The law is contrary to the nature of man. It was established this way. So that an honest man would come to Christ for all his needs.