In faith, however, everything is fulfilled by the single reception of faith, accomplished in the heart. Yet the power of this action is such that the whole Law and all the commandments appear fulfilled in it.
For whoever has faith has Christ, who is the end of the Law. Thus, by the predictive passage cited, the Apostle proved that Christ is the end of the Law.
He proved it both because what was pre-indicated in the Law is fulfilled in Him, and because the Law itself and the purpose for which the Law was given are fulfilled in Him.
The Law was given for righteousness. The one who believes in Christ becomes righteous, because in Him and through Him he receives grace.
This grace transforms the heart and fills it entirely with holy feelings and dispositions. In them the commandments are fulfilled, or from them the fulfillment of the commandments proceeds as a natural fruit.
If the fulfillment of the Law is impossible by any other means, then whoever does not receive faith in Christ out of zeal for the Law destroys the very thing the Law desires.
Or he goes against the Law. Is it not evident that such zeal is not according to understanding?
This is the Apostle’s thought in citing the indicated passage and pointing to the fulfillment of what is said in it through faith.
But since the work of faith is all-embracing, the word concerning it unavoidably touches other aspects of faith besides those under discussion. So also in the present passage, the Apostle suggests something else besides the immediate subject.
Legal righteousness requires labor and struggle, so that one’s deeds, at every time and in every place, may be conducted according to the Law.
Righteousness from faith, however, is accomplished wholly within. It has no need of a diversity of actions and expressions. Believe in the heart, and you are righteous.
Yet this does not mean that the work of faith is as easy as a feather lifted by the movement of air. Faith is an inward action.
For that very reason it is harder than works. What comes in it from grace acts easily. What belongs in it to man entails perceptible labor, though all of it is inward.
The movement of faith is a complete reordering of everything within. What undergoes reordering is old and deeply rooted. It cannot fail to assert its rights, acquired by long standing.
Thus it cannot fail to hinder the course of faith. This must be removed, and there is the struggle.
When faith says, “I believe,” it is a single and momentary action. But not everyone reaches this in one minute.
Faith is the greatest struggle, higher than all struggles, their root and foundation. Therefore the Apostle says: “Do not say in your heart,” who will bring Christ down to earth, or who will raise Him from the dead.
The Incarnation of the Son of God, His death, and His resurrection are the chief object of faith and preaching. Yet how many arguments has this always raised, and does it still raise, in the hearts of hearers?
The Apostle says: do not admit these arguments. “Do not say in your heart,” who can accomplish this, and how can this be accomplished.
Believe simply, like a child, overcoming all such arguments. “One must not enter into investigation concerning the Master’s divine economy, or doubt how the Only-begotten Son of God became man and, having accepted suffering, accomplished the resurrection. Rather, by faith one must bear the fruit of salvation” (Blessed Theodoret).
Chrysostom gives the same thought another shade: “So that, by proving this path convenient and brief, he might not suggest that it is unworthy of attention, see how the Apostle speaks at length about it: ‘Do not say in your heart.’ As negligence and slackness oppose virtue manifested in works. Making one incapable of labors, and as a very watchful soul is needed lest one surrender to this, so in the matter of faith thoughts arise that disturb and weaken the hearts of many. To repel them, the most watchful soul is needed. Therefore the Apostle exposes these very thoughts. He does here as he did when discussing Abraham. Having proved there that Abraham was justified by faith, lest someone conclude that this crown was acquired by him as a gift and for nothing, the Apostle praises the quality of faith and says. ‘Against hope, in hope he believed.’ By this he proved that Abraham needed an exalted soul, one that received what was beyond hope and was not offended by what was visible. He acts the same way here, proving that we need a mind that loves wisdom, a strong will, and one that seeks heavenly things. He did not simply say, ‘Do not say,’ but ‘Do not say in your heart.’ That is, do not even waver in thought or say within yourself, ‘How is this possible?’ Do you see that this is the distinctive property of faith? It leaves aside all earthly reasonings, seeks what is above nature, rejects the help of thoughts, and receives everything by being established on the omnipotence of God.”