How does faith relate to grace?

In Romans 4:16, Paul emphasizes that righteousness is by faith so that it might be by grace. This indicates that faith is not a work that earns salvation, but rather the instrument through which grace is received. If salvation were based on works, it would not be an act of grace; instead, it would be owed to us as a debt (Romans 4:4). Therefore, the relationship between faith and grace is foundational in Reformed theology, underscoring that salvation is solely a divine work, initiated and completed by God for those who believe. Believers can rest assured that their salvation is secure, not on any merit of their own, but entirely by His grace.