At the point of faith in Christ, God imputes Eternal Life and His own Righteousness to every believer and declares him righteous or justified (Romans 3:21-28).
Eternal life is eternal security. Eternal security rests in God’s Absolute Integrity. God accepted the Cross work of Christ as full and unconditional payment for sin and therefore he declares the believer righteous because of Christ. This is a permanent condition (See also 1 John 5: 9-13.)