Why is the concept of imputed righteousness significant in Sovereign Grace theology?

In Sovereign Grace theology, the concept of imputed righteousness is crucial because it teaches that believers are counted as righteous before God solely on the merit of Christ's perfect life and sacrifice. This idea is rooted in Scriptures such as 2 Corinthians 5:21, which states that God made Christ, who had no sin, to be sin for us, so that in Him we might become the righteousness of God. This doctrine emphasizes the grace of God in declaring sinners righteous, affirming that it is not based on any human effort or works but solely on faith in Christ. This understanding provides profound assurance to believers that their acceptance before God is secure, grounded in Christ's work rather than their fallibility.