How do we know that God's law is still relevant for Christians?

Despite the new covenant established through Christ, God’s law remains relevant as it exemplifies His holiness and justice. In Romans 3:31, Paul asks rhetorically, 'Do we then make void the law through faith? God forbid: yea, we establish the law.' This means that while believers are not under the law as a set of regulations for life, the purpose of the law continues to serve as a guide that drives us to our need for Christ, illustrating our sinful nature and the holiness of God. Thus, the law is established through gospel faith and helps us appreciate the grace of God in Christ while maintaining an understanding of His moral standards.