 It says in Galatians chapter 3, the purpose of the law is to lead us to Christ. The purpose of the law is to show you, hey, you can't do it. God's standard is perfection and you can't do it and you come up short and woe is me for I am undone. The purpose of the law is to show you that you're a sinner and you're lost and you desperately need Jesus. The law has become our tutor, the scripture says, to lead us to Christ.