How do we know that God saves us by grace alone?

The doctrine of justification by grace alone is grounded in Scripture, particularly highlighted in passages like Ephesians 2:8-9, which assert that we are saved by grace through faith, and that not of ourselves; it is the gift of God. This truth is essential to the Gospel, revealing that our salvation is not based on our works but solely on Christ's perfect sacrifice. Furthermore, the teachings of Paul throughout the New Testament confirm that our righteousness is derived from Christ, leading to the conclusion that we are accepted by God purely due to His grace and mercy.