The need to distinguish these two kinds of justification is especially clear from what is said below in chapter 11. The Apostle says that the Israelites, except for the remnant preserved "by grace and not by works" (Rom 11:6), "were hardened" (Rom 11:7), "fell and were diminished" (Rom 11:12), were "rejected" (Rom 11:15), and "were broken off" (Rom 11:17). Through this the Gentiles received "salvation" (Rom 11:11), "riches" (Rom 11:12), "reconciliation" (Rom 11:15), and "were grafted in and became partakers of the root and richness of the olive tree" (Rom 11:17).
Yet the Apostle makes it sufficiently clear that this reconciliation and enrichment are not final. He adds this admonition to the Christian from among the Gentiles: "Do not be proud," "but fear. Behold the goodness and severity of God: severity toward those who fell, but goodness toward you, if you continue in His goodness. Otherwise you also will be cut off" (Rom 11:20-22).
Thus, although the first reconciliation with God is given through faith alone in the merits of Christ, Who suffered for us, final reconciliation and justification are given to the one who follows in His steps. According to the words of the Apostle Paul in Rom 12:1, he must present his body "as a living sacrifice, holy and acceptable to God." In short, he must show faith by works.
Of course, our life is so sinful that we never hope to be justified by our works. We constantly beseech God not to enter into judgment with us. Yet this does not mean that we are not obliged to care for works, or that they are not required of us.