The New Testament, while affirming the security of the believer, also contains strong warnings against willful sinning and apostasy, indicating that such behaviors are incompatible with a regenerated life. Hebrews 10:26-27 warns, "For if we go on sinning deliberately after receiving the knowledge of the truth, there no longer remains a sacrifice for sins, but a fearful expectation of judgment, and a fury of fire that will consume the adversaries." This passage, among others, suggests that a lifestyle of deliberate sin is evidence of an unregenerate heart and calls into question the genuineness of one's faith. The apostle Paul echoes this in Galatians 5:21, stating that those who practice such things will not inherit the kingdom of God, urging believers to live by the Spirit and not gratify the desires of the flesh.
Therefore, while the grace of God in salvation is profoundly secure, it is also transformative, leading to a life increasingly characterized by holiness and obedience. True faith in Christ manifests in a life that seeks to honor God, marked by repentance from sin and growth in righteousness. The biblical call to perseverance and holiness is not a threat to the believer's security but a characteristic of genuine faith. It's important to approach this topic with humility, recognizing the balance Scripture maintains between the assurance of salvation and the call to live a life worthy of the calling we have received in Christ Jesus.