Romans 4

     4:1-5.  Paul now turns to the narrative portions of the Law to prove that the justification of sinners can only be by faith alone, as in the case of Abraham.  Even supposing Abraham had been justified by works, it would have been nothing to boast about before God (2).  He would only have done his duty, that which he ought to have done (Luke 17:10; cf. Jer.9:23 ff.).  He could have earned his wage (4), but as an ungodly man, he needed the unmerited favor that can only come by grace (5).  But to receive it, Abraham had to believe that God was able to do what he promised.  It was his faith in the work God promised to do for him that was reckoned to him as righteousness, and made him an heir to God’s promises.

     4:6-8.  As a sinner, David also testifies (Ps.32) that his hope of blessing is that the Lord will cover his sin, and not take it into account.  Doing works of the Law could never do this.  It is in fact the Law that condemns him.

     4:9-10.  Nor does Abraham’s blessing come because of circumcision, for he was already reckoned as righteous by faith before being circumcised.

     4:11-12.  Circumcision (to which baptism now corresponds) does not secure righteousness, but is a sign and seal of that which is obtained by faith.  (Since circumcision was given to all infant boys born under that covenant, it follows that the children of believing parents also have a right to baptism, the sign and seal of the same thing under the new covenant; cf. Col.2:11 ff.; see notes at Acts 16:31-34.)

     4:13-15.  Law keeping had nothing to do with the blessing promised to Abraham, which was given apart from the Law (3:21 f.).  If we could become heirs of salvation by our own efforts under the Law, God would never have needed to make the promise by which we obtain righteousness by faith, for we would already have earned it on our own.  Christ’s death would have been rendered unnecessary and pointless (14).  But on the contrary, the Law could never be the way sinners are saved (15).

     4:16-17.  For this reason it must be by faith in accordance with God’s grace, and Abraham is the spiritual father of all the faithful, whether they are Jews having the Law, or Gentiles who have it not.  In the gospel there is no distinction (2:11, 3:22).  For those who believe, God raises the dead and creates life even where there was none, for he is faithful to his promise, and able to deliver (Heb.11:19; Luke 3:8; John 8:39).

     4:18-25.  Our hope of glory rests on the same faith we see rewarded in our father Abraham, for these things were written for our sakes as well (23-24).  Just as Abraham looked forward to promises that were fulfilled in Jesus, so we look back to him with even stronger support.  If Jesus died for our transgressions, his being raised proves his death made full satisfaction for them.  We are no longer under the condemnation of God’s Law, but are justified (25).  See WSC, question 33.