Romans 3-4

Paul answers what is essetially a stupid question to head up chapter 3. "Should we sin more to show how much better God is than us?" No. We don't need to make God look good or faithful or sinless or forgiving or anything else we try to excuse our own behavior with. God is faithful. We are not. God is righteous. We are not. No one understands. No one seeks Him. And no one will be declared righteous by observing the law, as Paul points out. The law is there to show us that we are sinners in need of a Savior.

That's where Christ comes in. We all sin and fall short, but God presented Christ as our sacrifice of atonement, though faith. That fulfills justice. So we have nothing to brag about in salvation. Our justification has nothing to do with our observation of the law. Jew or Gentile.

Paul's discussion of Abraham being justified by faith is a beautiful description of how we are saved in the same manner as the father of the Israelites.

God calls things that are not as though they were. God's knowledge of the future is being discussed here, over the objection of the open theists.