At the point of faith in Christ, God permanently 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 (Reference 1 John 5: 9-13.)