How do we know that salvation is by grace and not works?

The distinction between grace and works is central to Reformed theology. Romans 4:4-5 states, 'Now to him that worketh is the reward not reckoned of grace, but of debt. But to him that worketh not, but believeth on him that justifieth the ungodly, his faith is counted for righteousness.' This illustrates that if salvation were based on our works, it would be a debt owed, rather than a gracious gift. Furthermore, Galatians 3:10 reminds us, 'For as many as are of the works of the law are under the curse,' emphasizing that no one can achieve righteousness through the law. Instead, it is God's unmerited favor towards us that secures our salvation.