The Purpose of/for God’s Moral Law,
The Law was given with the creation of the angels as free will required a bulwark, a standard, by which the living, all created beings, could survive in community and life be sustained with order and peace. The Law defines God’s holiness and His righteous requirements. The moral law was extant before the beginning of Time and accused the Devil of covetousness and motivated his extrication from God’s Kingdom and initiated the creation of matter, Time, the Heavens and the Earth, our genome; these, as a repository and method of dealing with sin apart from the Kingdom where nothing impure is permitted to exist (Rev 21:27); in fact, the primary reason the Son of God appeared within the Realm of Time was to destroy the works of the Devil (1 John 3:b).
The moral Law is NOTHING new; the Torah is NEW as it was given to a specific people for a specific dispensation to codify God’s righteous requirements and prepare the way for Messiah. As a Christian, I am not under Law but under Grace in my Lord Jesus. If you desire to be under Law…that’s your prerogative but the Law will not provide you righteousness (a right standing) with God the Father as you are a sinner (Romans 3:23) and the Law only defines your sin void atonement (Romans 3:20). Righteousness with the Father will ONLY manifest by grace (a gift you cannot earn) through faith (trusting-believing) in Jesus as your Messiah who died to pay your sin-debt; again, those who have trusted in Jesus as Lord are not under Law but under God’s grace and these alone will enter the Kingdom of God.