How do we know salvation is not based on our personal growth?

The assurance of salvation is grounded in the work of Christ, rather than our own performance or progress. As stated in Romans and Philippians, salvation comes from God's grace and the righteousness of Christ, which is received through faith. Paul illustrates this by recounting his own background and realization that his previous credentials meant nothing when compared to the excellency of knowing Christ (Philippians 3:8-9). Furthermore, our sanctification is not gradual improvement over time but a positional reality achieved through Christ’s once-for-all sacrifice (Hebrews 10:10). Our confidence should then rest solely in His completed work and not in our perceived spiritual progress.