How do we know that believers cannot fall from God's grace?

Believers cannot fall from God's grace because their salvation is rooted in God's eternal promise rather than in their own works or merits. Romans 8:35-39 proclaims that nothing can separate us from the love of God in Christ Jesus, affirming our security in Him. True believers may struggle with sin or experience trials, but their faith rests on the assurance that God’s grace is irrevocable. The passage points to the unchanging nature of God's love and grace, emphasizing that it is not dependent on our actions or feelings, but solely on God's faithfulness and the redemptive work of Christ. Therefore, while believers may falter, they will never fall away from the grace that sustains them.