Why is frustrating the grace of God a serious matter?

Frustrating the grace of God is a grave concern because it directly impacts how we perceive the sufficiency of Christ's work. In Galatians 2:21, Paul emphasizes that if righteousness comes by the law, then Christ's death is in vain. This highlights the seriousness of leaning on any personal merit for salvation as it effectively annuls the grace of God. Works-based salvation could lead one to believe they have a part in their own justification, which contradicts the biblical teaching of grace. It is important to affirm that our redemption solely depends on what Christ accomplished, ensuring that salvation is attributed entirely to His merits.