The Bible distinguishes between the covenant of works, which is based on human effort, and the covenant of grace, which is fulfilled in Christ's finished work.
The Scriptures present two distinct covenants: the covenant of works and the covenant of grace. The former demands that we do, while the latter assures us that it is done, exemplified in the sacrifices of Cain and Abel, where God's favor rested upon Abel's offering of a lamb as a type of Christ. In Romans 8:3-4, we learn that 'God sending his own Son in the likeness of sinful flesh, and for sin, condemned sin in the flesh, that the righteousness of the law might be fulfilled in us.' Thus, those who cling to the old covenant of works are doomed to fail, as only the new covenant of grace can save us.
Commentary