"What then shall we say that Abraham, our forefather, discovered in this matter? If, in fact, Abraham was justified by works, he had something to boast about - but not before God." (Romans 4:1-2)
Abraham was the patriarch of the Jewish race. As patriarch, he played an important role in establishing the nation of Israel. The Jews clung to the covenant that God had established with Abraham, relying on it to be justified. Since everything could be traced back to Abraham, Paul is using him as evidence to support his amazing claim of faith in the previous verses.
The questions hanging in the air is, what good was Abrahams works? The Jews claimed that to be in right standing with God, you must be circumcised and adhere to the Law. They were relying on the token of their covenant with God as the means for salvation. However Paul just declared in Romans 3:28, that a man is justified by faith apart from observing the law. Paul is stating that Abraham had nothing to boast about before God. So in fact, the answer to this question is, that Abraham's works were not good enough to grant him justification in His God's sight.
If Abraham's works weren't good enough, how was Abraham justified? The same way we are, by faith. Abraham is called the Father of Many Nations because he believed God and had faith in His promises. Because of it, He had glimpses into the extent of the fulfillment of that promise. This is a simple truth but one the Jews had exchanged for a complicated system of works. Paul is reminding them that faith has always been the means of salvation. It is nothing we have done or can ever do to obtain it.
Why is this important to know? This is important because everything rests on Faith. We must know, that that it is our faith that credits righteousness to us. Otherwise, trying to obtain justification by works has the potential to launch you into a life of doing and performing with a hope that will never be realized. It won't benefit you, it will only wear you out. Faith in God's promise to you, only brings about hope and rest. Today, may you rely in what our father Abraham discovered about faith, that it is all it takes and that it pleases God in every way!