“If you confess with your mouth the Lord Jesus, and believe in your heart that God has raised Him from the dead, you shall be saved.” Then again that we may not seem to be making it contemptible by showing it to be easy and cheap, observe how he expands his account of it. For he does not come immediately to the words just given, but what does he say? “But the righteousness which is of faith says on this wise; Say not in your heart, Who shall go up into heaven? (that is, to bring Christ down); or, Who shall descend into the deep? (that is, to bring up Christ again from the dead.”) For as to the virtue manifested in works there is opposed a listlessness, which relaxes our labors, and it requires a very wakeful soul not to yield to it: thus, when one is required to believe, there are reasonings which confuse and make havoc of the minds of most men, and it wants a soul of some vigor to shake them thoroughly off. And this is just why he brings the same before one. And as he did in Abraham's case, so he does here also. For having there shown that he was justified by faith, lest he should seem to have gotten so great a crown by a mere chance, as if it were a thing of no account, to extol the nature of faith, he says, “Who against hope believed in hope, that he might become the father of many nations. And being not weak in faith, he considered his own body now dead, and the deadness of Sarah's womb. He staggered not at the promise of God through unbelief; but was strong in faith, giving glory to God; and being fully persuaded that what He had promised He was able also to perform”: so he showed that there is need of vigor, and a lofty soul, that takes in things beyond expectation, and stumbles not at appearances. This then he does here also, and shows that it requires a wise mind, and a spirit heavenly (Gr. heaven-reaching) and great. And he does not say merely, “Say not,” but, “Say not in your heart,” that is, do not so much as think of doubting and saying with yourself, And how can this be? You see that this is a chief characteristic of faith, to leave all the consequences of this lower world, and so to seek for that which is above nature, and to cast out the feebleness of calculation, and so to accept everything from the Power of God. The Jews, however, did not merely assert this, but that it was not possible to be justified by faith. But himself turns even what had taken place to another account, that having shown the thing to be so great, that even after it had taken place it required faith, he might seem with good reason to bestow a crown on these: and he uses the words which are found in the Old Testament, being always at pains to keep quite clear of the charges of love of novelties, and of opposition to it. For this, which he here says of faith, Moses says to them of the commandment, so showing that they had enjoyed at God's hand a great benefit. For there is no need to say, he means, that one must go up to heaven, or cross a great sea, and then receive the commandments, but things so great and grand has God made of easy access to us. And what means the phrase, “The Word is near you?” That is, It is easy. For in your mind and in your tongue is your salvation. There is no long journey to go, no seas to sail over, no mountains to pass, to get saved. But if you be not minded to cross so much as the threshold, you may even while you sit at home be saved. For “in your mouth and in your heart” is the source of salvation. And then on another score also he makes the word of faith easy, and says, that “God raised Him from the dead.” For just reflect upon the worthiness of the Worker, and you will no longer see any difficulty in the thing. That He is Lord then, is plain from the resurrection. And this he said at the beginning even of the Epistle. “Which was declared to be the Son of God with power... by the resurrection from the dead.” But that the resurrection is easy too, has been shown even to those who are very unbelieving, from the might of the Worker of it. Since then the righteousness is greater, and light and easy to receive, is it not a sign of the utmost contentiousness to leave what is light and easy, and set about impossibilities? For they could not say that it was a thing they declined as burdensome. See then how he deprives them of all excuse. For what do they deserve to have said in their defence, who choose what is burdensome and impracticable, and pass by what is light, and able to save them, and to give them those things which the Law could not give? All this can come only from a contentious spirit, which is in a state of rebellion against God. For the Law is galling (ἐ παχθὴς), but grace is easy. The Law, though they dispute never so much, does not save; Grace yields the righteousness resulting from itself, and that from the Law likewise. What plea then is to rescue them, since they are disposed to be contentious against this, but cling to that to no purpose whatever? Then, since he had made a strong assertion, he again confirms it from the Scripture.
Ver. 11-13. “For the Scripture says,” he proceeds, “Whosoever believes in Him, shall not be ashamed. For there is no difference between the Jew and the Greek; for the same Lord over all is rich unto all that call upon Him. For whosoever shall call upon the Name of the Lord shall be saved.”
Source: Homilies on Romans (New Advent)