How do we know that believers are eternally secure?

The assurance of believers' eternal security is deeply rooted in the scriptural affirmations of Christ's prayer and covenant promises. In John 17:1-2, Jesus asks the Father to glorify those whom He has given Him, an assertion that reflects His confidence in the security of their salvation. This prayer is not a mere request but is based on Christ's fulfillment of divine justice and His role as the mediator of the new covenant.

The belief in eternal security is vital in Reformed theology because it underscores the totality of Christ’s redemptive work. If any believer were to finally perish, it would reflect inadequately on Christ's power and the efficacy of His work. Instead, the promises throughout scripture affirm that God will bring all of His chosen ones to glorification, which shapes the believer's identity and purpose in their daily walk with God, as they are assured of His unbreakable love and faithfulness.