How do we know grace alone through Christ alone is true?

The doctrine of salvation by grace alone, through Christ alone, is foundational in Reformed theology and is rooted in Scripture. Ephesians 2:8-9 explicitly states that we are saved by grace through faith, and that not of ourselves; it is the gift of God, not of works, lest any man should boast. This positions faith as a gift from God rather than an achievement, ensuring that no one can claim credit for their salvation. It underscores the sufficiency of Christ’s atoning work, giving believers confidence in the complete and perfect nature of our salvation.