Mankind in his natural state is a law breaker.
Therefore by the deeds of the law there shall no flesh be justified in his sight: for by the law is the knowledge of sin. (Romans 3:20 KJV)
The law was given to Moses by God for use as a tool in convicting mankind of his natural inclination to sin. It is a spiritual pricking or awakening of his conscious which pokes holes in man’s estimation of himself encouraging him to peer through the holy lens of God seeing his natural sinful imperfections in the light of God’s perfection.
Mankind has no goodness or worth aside from the goodness, grace, and mercy of God. It is only when man makes the choice to turn from relying upon his own hindered efforts of moral goodness and faltering attempts at keeping the law that he is adorned in God’s robe of righteousness and covered in the precious blood of Jesus Christ as it permeates every crack and crevice of his thirsty spiritual heart condition.