How does legalism undermine the grace of God?

Legalism directly undermines the grace of God by implying that human efforts or adherence to the law can secure a believer's standing before God. Paul makes it clear in Galatians 2:21 that if righteousness could be attained through the law, then Christ died for nothing. This perspective leads to a self-righteousness that is contrary to the heart of the gospel, which centers on grace alone through faith alone in Christ alone. Such an attitude hinders believers from experiencing the full power of the grace found in Jesus and can ultimately lead them away from the true freedom of the gospel.