How do we know that all believers will be preserved by grace?

The doctrine of perseverance—that true believers will be preserved by God's grace—is biblically supported in passages like Hebrews 10:39, where it states, 'But we are not of them who draw back unto perdition; but of them that believe to the saving of the soul.' This assurance rests on the sovereignty of God who initiates and sustains faith in His elect. It is not based on human effort, but on divine promise and the intercessory work of Christ, who prays for the faith of His people (Luke 22:31-32).

In contrast to Judas, who fell into apostasy and eternal destruction because he never possessed true faith, Peter's experience shows a different outcome. His denial, though grievous, did not sever his relationship with Christ as it led him to genuine repentance and restoration. This distinction is critical; true believers may stumble due to weakness and sin, but God's grace is effective in restoring them. Thus, the assurance of salvation is not merely a hope, but a security rooted in God's unchanging purpose and Christ's finished work on the cross.