Having shown that every human being is a hopelessly lost sinner, Paul now shows the way for us to be made right with God (justified). Since Christ has shed his blood as an atonement, all who put their trust in him (have faith) will be forgiven and received back into fellowship with God, which is true life.
Is this idea something new? No, already at the beginning of the establishment of God’s people, Abraham, our spiritual ancestor, “believed God, and it was counted to him as righteousness” (4:3 ESV).
As a result of being justified by faith, we have peace and joy and hope and the assurance that even the difficulties of this life are working for our benefit (7:1-5). The sin of Adam has had tragic consequences in the lives of all of us, but now through Christ we who believe receive great blessings.
If justification is by faith and not as the result of our good works, does this mean that it does not matter if we keep on sinning? Paul is horrified by such a conclusion, for we are now united to Christ by faith, and such a union can only produce good works.
We are not saved by keeping the law of the Old Testament, for we sinners are unable to keep it perfectly. The law has a different, but important role; it convicts us of our sin so we will flee into the open arms of Christ.