Can a believer lose the grace of God once they have it?

According to Reformed theology, the assurance of salvation is rooted in the sovereignty of God and His faithfulness to His promises. John 10:27-28 assures us that Jesus gives eternal life to His sheep, and they will never perish. This affirms that those who are genuinely regenerated by God’s grace cannot lose their salvation or the grace bestowed upon them, since it is God who sustains their faith. The idea that one could be regenerated and then lose that state impugns God’s omnipotence and the effectiveness of Christ’s atonement. Thus, true believers rest in the assurance that their salvation and God’s grace are secure.