The interpretation timeline
Romans 10:10 Douay-Rheims

For, with the heart, we believe unto justice; but, with the mouth, confession is made unto salvation.

A.D. 108 – 1871 10 witnesses 16 excerpts

Patristic

before A.D. 750
108
A.D.
c. A.D. 50–107
“It is better for a man to be silent and be [a Christian], than to talk and not to be one. "The kingdom of God is not in word, but in power." Men "believe with the heart, and confess with the mouth," the one "unto righteousness," the other "unto salvation." It is good to teach, if he who speaks also acts. For he who shall both "do and teach, the same shall be great in the kingdom." Our Lord and God, Jesus Christ, the Son of the living God, first did and then taught, as Luke testifies, "whose praise is in the Gospel through all the Churches."”
Source
215
A.D.
c. A.D. 150–215
“But it is God that makes proclamation to us, and He must be believed. "For with the heart man believeth unto righteousness; and with the mouth confession is made unto salvation. Wherefore the Scripture saith, Whosoever believeth on Him shah not be put to shame." "With the heart man believeth unto righteousness, and with the mouth confession is made unto salvation. Wherefore the Scripture saith, Whosoever believeth on Him shall not be ashamed; that is, the word of faith which we preach: for if thou confess the word with thy mouth that Jesus is Lord, and believe in thy heart that God hath raised Him from the dead, thou shalt be saved." There is clearly described the perfect righteousness, fulfilled both in practice and contemplation.”
Source
220
A.D.
Tertullian Patristic
c. A.D. 150–220
“For, when one reads of God as being "the searcher and witness of the heart; " when His prophet is reproved by His discovering to him the secrets of the heart; when God Himself anticipates in His people the thoughts of their heart, "Why think ye evil in your hearts? " when David prays "Create in me a clean heart, O God," and Paul declares, "With the heart man believeth unto righteousness," and John says, "By his own heart is each man condemned; " when, lastly, "he who looketh on a woman so as to lust after her, hath already committed adultery with her in his heart," -then both points are cleared fully up, that there is a directing faculty of the soul, with which the purpose of God may agree; in other words, a supreme principle of intelligence and vitality (for where there is intelligence, there must be vitality), and that it resides in that most precious part of our body to which God especially looks: so that you must not suppose, with Heraclitus, that this sovereign faculty of which we are treating is moved by some external force; nor with Moschion, that it floats about through the whole body; nor with Plato, that it is enclosed in the head; nor with Zenophanes, that it culminates in the crown of the head; nor that it reposes in the brain, according to the opinion of Hippocrates; nor around the basis of the brain, as Herophilus thought; nor in the membranes thereof, as Strato and Erasistratus said; nor in the space between the eyebrows, as Strato the physician held; nor within the enclosure of the breast, according to Epicurus: but rather, as the Egyptians have always taught, especially such of them as were accounted the expounders of sacred truths; in accordance, too, with that verse of Orpheus or Empedocles:”
Source
“And we know the quality of the hortatory addresses of carnal conveniences, how easy it is to say, "I must believe with my whole heart; I must love God, and my neighbour as myself: for `on these two precepts the whole Law hangeth, and the prophets, 'not on the emptiness of my lungs and intestines.”
397
A.D.
Ambrose of Milan Patristic
A.D. 339–397
“With these twin trumpets of heart and mouth we arrive at that holy land, viz., the grace of resurrection. So let them always sound together in harmony for us, that we may always hear the voice of God. Let the utterances of the angels and prophets arouse us and move us to hasten to higher things.”
407
A.D.
John Chrysostom Patristic
A.D. 347–407
“The understanding must be strongly fixed in pious faith, and the tongue must herald forth by its confession the solid resolution of the mind.”
“And what meaneth the phrase, "The Word is nigh thee?" That is, It is easy. For in thy mind and in thy tongue is thy 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 thy mouth and in thy 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.”
Source
430
A.D.
Augustine of Hippo Patristic
A.D. 354–430
“The innumerable and multiple rites by which the Jewish people had been oppressed have been taken away, so that in the mercy of God we might attain salvation by the simplicity of a confession of faith.”
“Did not almost all those who disowned Christ in the presence of their persecutors keep in their hearts what they believed about him? Yet, for not making with their mouth profession of faith unto salvation they perished, except those who repented and lived again.”
“This condition is fulfilled at the time of baptism, when faith and profession of faith are all that is demanded for one to be baptized.”
“This profession of faith is the creed which you will be going over in your thoughts and repeating from memory.”
“We who expect to reign in everlasting righteousness can only be saved from this wicked world if while for our neighbor's salvation we profess with our lips the faith which we carry about in our heart, we exercise a pious and careful vigilance to see that this faith in us is not sullied in any point of belief by the deceitful snares of heretics.”
Source

Scholastic

c. 1100 – 1500
1273
A.D.
Thomas Aquinas Catholic
1225–1274
“After the Apostle had, in expounding the word of Moses, set down beforehand that confession of the mouth and faith of the heart work salvation—proposing this by way of example in two particulars, of which Moses seemed to have made mention—here he proves in universal terms what he had said. And concerning this he does three things. First he shows that through faith and confession man attains salvation; second he sets down the order of salvation, at the words how then shall they call upon, etc.; third he draws a certain conclusion from what has been said, at the words therefore faith is from hearing, and so on. Concerning the first he does three things. First he sets forth what he intends, saying: I rightly say that if you confess with your mouth and believe in your heart, you will be saved; for with the heart one believes, on man's part, unto righteousness, that is, unto this, that he may attain righteousness through faith. Above, chapter 5: being therefore justified from faith. He says pointedly with the heart one believes, that is, by the will. For as to the other things which pertain to the outward worship of God, a man can perform them unwillingly, but he cannot believe except willingly. For the intellect of the one believing is not determined to assent to the truth by the necessity of reason, as is the intellect of the one who knows, but by the will; and therefore knowing does not pertain to man's righteousness, which is in the will, but believing does. Genesis 15: Abraham believed God, and it was reputed to him unto righteousness. But after man has been justified through faith, it is necessary that his faith work through love in order to attain salvation. Hence he adds, but with the mouth confession is made unto salvation, namely, unto the attainment of eternal salvation. Isaiah 51: but my salvation shall be forever. Now there is a threefold confession necessary for salvation. First, indeed, the confession of one's own iniquity, according to Psalm 31: I said, I will confess against myself my injustice to the Lord, which is the confession of the penitent. The second confession is that by which man confesses the goodness of God who mercifully bestows benefits, Psalm 117: confess to the Lord, for he is good, and this is the confession of one giving thanks. The third is the confession of divine truth, Matthew 10: everyone who shall confess me before men, I also will confess him before my Father; and this confession is that of the believer, of which the Apostle now speaks. This, however, is necessary for salvation according to place and time, namely, when someone's faith is demanded, that is, by a persecutor of the faith, or when another's faith is endangered—just as prelates especially ought to preach the faith to their subjects. And for this reason the baptized are anointed with chrism on the forehead with the sign of the cross, so that they may not be ashamed to confess the Crucified himself. Above, chapter 1: for I am not ashamed of the Gospel. And so it is likewise with all the acts of the virtues, which are necessary for salvation according to place and time. For the affirmative precepts which are given concerning these things bind always, but not for always. Second, at the words for the Scripture says, etc., he proves it by authority, saying: for the Scripture says, namely Isaiah 28: whoever believes in him, namely with a formed faith, shall not be confounded, that is, as one falling short of salvation. Ecclesiasticus 2: you who fear the Lord, believe him, and your reward shall not be made void. Our text, however, has: he who shall have believed, let him not hasten, as was said above. Third, at the words for there is no distinction, etc., he proves that this is to be understood universally, since Isaiah proposes it without qualification. And first he sets forth what he intends, saying: therefore it was said whoever believes, etc., for there is no distinction in this regard between Jew and Greek. Colossians 3: where there is no Gentile and Jew, circumcision and uncircumcision, and so on. Second, he proves it by an argument which rests on two grounds, the first of which he touches when he says, for the same is Lord of all. Above, chapter 3: is he the God of the Jews only? Is he not also of the Gentiles? Psalm 46: God is king of all the earth. And therefore it belongs to him to provide for the salvation of all. He touches the second ground when he says, rich toward all who call upon him. For if he were not of such goodness as would suffice for the satisfaction of both, one might think that he would not provide for all believers; but the riches of his goodness and mercy are unfailing. Above, chapter 2: or do you despise the riches of his goodness? Ephesians 2: but God, who is rich in mercy, and so on. Third, he proves the same point by the authority found in Joel 2: whosoever shall call upon the name of the Lord shall be saved. Now to call upon is to call him into oneself through affection and devout worship. Psalm 90: he shall call upon me, and I will hear him. Then, at the words how then shall they call upon, etc., he sets down the order by which someone is called unto salvation, which is from faith. And concerning this he does two things. First he shows that the things which are later in this order cannot exist without the prior things; second he shows that, given the prior things, it is not necessary that the later things be given, at the words but not all obey the Gospel. Concerning the first he does two things. First he sets down the order of the things required for salvation; second he confirms what he had assumed by an authority, at the words as it is written. Now first he sets down five things in order, beginning from invocation, upon which, according to the authority of the prophet, salvation follows. He says therefore how then shall they call upon him in whom they have not believed? As if to say: without doubt invocation cannot bring about salvation unless faith precedes it. Now invocation pertains to confession of the mouth, which proceeds from faith of the heart. Psalm 115: I believed, therefore have I spoken. 2 Corinthians 4: we believed, therefore we also speak. Second, he ascends or proceeds from faith to hearing, saying, or how shall they believe him whom they have not heard? For a man is said to believe those things which are told him by others which he himself does not see. John 4: now we believe not for your saying, for we ourselves have heard, and know that this is indeed the Savior of the world, and so on. Now there is a twofold hearing: one indeed interior, by which someone hears from God revealing, Psalm 84: I will hear what the Lord God shall speak in me; the other, however, is a hearing by which someone hears from a man speaking outwardly. Acts, chapter 10: while Peter was yet speaking these words, the Holy Spirit fell upon all who heard the word. Now the first hearing does not pertain commonly to all, but properly pertains to the grace of prophecy, which is a grace freely given distinctly to some, but not to all, according to that saying, 1 Corinthians 12: there are divisions of graces. But since he is now speaking of that which can pertain indistinctly to all, according to what he said above, for there is no distinction, it remains that this is to be understood of the second hearing. And therefore he adds: how then shall they hear without a preacher? For exterior hearing is a certain passion of the hearer, which cannot exist without the action of one speaking. Hence also the Lord commanded his disciples, Matthew, last chapter: going into the whole world, preach the Gospel to every creature. But as for the things which are of faith, preachers do not have them from themselves, but from God. Isaiah 21: what I have heard from the Lord God of hosts I have declared to you. 1 Corinthians 11: for I have received of the Lord that which also I delivered unto you. And therefore the Apostle, fourth, adds, and how shall they preach unless they be sent? As if to say, not worthily. Jeremiah 23: I did not send them, and they ran. Now some are sent by the Lord in two ways. In one way, immediately by God himself through interior inspiration. Isaiah 48: and now the Lord God has sent me, and his spirit. Now the sign of this sending is sometimes indeed the authority of Sacred Scripture; hence John the Baptist, when he was asked who he was, adduced the authority of a prophet, saying: I am the voice of one crying in the desert, make straight the way of the Lord, as Isaiah the prophet said, as is read in John 1. Sometimes, however, the sign of this sending is the truth of the things announced. Hence, conversely, it is said in Deuteronomy 18 that this shall be the sign: that if a prophet shall foretell in the name of the Lord and it shall not come to pass, the Lord has not spoken this. Sometimes, indeed, the sign of this sending is the working of a miracle. Hence it is said in Exodus 4 that when Moses had said to the Lord: they will not believe me, nor hear my voice—namely, those to whom I am sent—the Lord gave him the power of working signs. Yet these last two do not sufficiently demonstrate a sending from God, especially when someone announces something contrary to the faith. For it is said in Deuteronomy 13: if there should arise in the midst of you a prophet, and he should foretell a sign and a wonder, and that should come to pass which he spoke, and he should say to you, let us go and follow strange gods, you shall not hear the words of that one. In the other way, some are sent by God through the mediation of the authority of prelates, who hold the place of God. 2 Corinthians 8: we have sent with him our brother, whose praise is in the Gospel throughout all the churches. Then, when he says as it is written, he brings in an authority to prove this last point, which he had said concerning the sending of preachers, saying as it is written, namely Isaiah 52: how beautiful are the feet of them that preach peace, of them that preach good things—where our text has it thus: how beautiful upon the mountains are the feet of him that preaches and announces peace, that announces good. And likewise it is found in Nahum 1: behold upon the mountains the feet of him that brings good tidings and announces peace. Now in these words, first, the progress of preachers is commended, when he says how beautiful are the feet, which can be understood in two ways. In one way, so that by feet is understood their progress, namely because they proceed in an orderly manner, not usurping to themselves the office of preaching. Canticles 7: how beautiful are your steps in your shoes, O daughter of a prince. In the other way, by feet can be understood the affections, which have rectitude, when they announce the word of God not with the intention of praise or gain, but for the sake of the salvation of men and the glory of God. Ezekiel 1: their feet, straight feet. Second, he touches on the matter of preaching, which indeed is twofold. For they preach those things which are useful for the present life, which he designates when he says: that preach peace, namely a threefold peace. First, indeed, they announce the peace which Christ made between men and God. 2 Corinthians 5: God was in Christ, reconciling the world to himself. And he has placed in us the word of reconciliation. Above, chapter 5: let us have peace with God through Jesus Christ. Second, they announce the peace to be had with all men. Below, chapter 12: if it be possible, as much as is in you, having peace with all men. Third, they announce those things by which a man can have peace within himself. Psalm 118: much peace have they that love your law, O Lord. And under these three are contained all the things which in this life are useful for salvation, whether with regard to God, or with regard to one's neighbor, or with regard to oneself. They also preach those things which we hope to have in the other life. And as to this he says, that preach good things. Luke 12: he shall set him over all his goods. Then, when he says but not all obey the Gospel, etc., he shows that from the prior things the later things do not always follow. For although it cannot be that someone believes unless he hears from a preacher, nevertheless not everyone who hears from a preacher believes, and this is what he adds, but not all obey the Gospel. 2 Thessalonians 3: for all men have not faith. Now he says this in order to show that the exterior word of the one speaking is not a sufficient cause of faith, unless the heart of the man is drawn interiorly by the power of God speaking, John 6: everyone who has heard from my Father, and has learned, comes to me. And thus that men believe is not to be attributed to the diligence of the preacher. By this also it is shown that not all unbelievers are excused from sin, but only those who do not hear and do not believe. John 15: if I had not come, and had not spoken to them, they would not have sin; but now they have no excuse for their sin. And this also is more consonant with what the Apostle will say afterward. Second, he brings in an authority for this, when he adds, for Isaiah says: Lord, who has believed our hearing? As if he were to say: few. Ezekiel 2: unbelievers and subverters are with you. Micah 7: I have become as one that gathers grapes in the autumn gleaning. This indeed Isaiah said, foreseeing the future unbelief of the Jews. Ecclesiasticus 48: he saw the last things by a great spirit, and so on. He says, moreover, our hearing, either on account of what they heard from God—as is said in Obadiah 1: we have heard a report from the Lord, and he has sent ambassadors to the nations—or on account of what men heard from the apostles. Ezekiel 33: they hear your words, and do them not. Then, when he says therefore faith is from hearing, etc., he draws the conclusion from what has been said, saying: therefore, since some do not believe unless they have heard, faith is from hearing. Psalm 17: at the hearing of the ear he has obeyed me. But it seems to be to the contrary that faith is a virtue divinely infused. Philippians 1: to you it is given, that you should believe in him. It must therefore be said that two things are required for faith: one of which is the inclination of the heart to believe, and this is not from hearing, but from the gift of grace; the other is the determination concerning what is to be believed, and this is from hearing. And therefore Cornelius, who had a heart inclined to believe, needed that Peter be sent to him, who might determine for him what was to be believed. Now from what he had said: how shall they hear without a preacher? and how shall they preach unless they be sent?, he concludes, but hearing, namely of believers, is through the word of preachers, which is the word of Christ, either because it is about Christ, 1 Corinthians 1: we preach Christ Jesus, or because they have it from Christ that they are sent, 1 Corinthians 11: for I have received of the Lord that which also I delivered unto you.”

Post-Reformation

c. 1650 – 1900
1771
A.D.
John Gill Reformed
1697–1771
“For with the heart man believeth unto righteousness,.... The apostle here explains the nature and use both of faith and confession; as true faith does not lie in the bare assent of the mind to the Gospel, or any truth contained in it, respecting the person and office of Christ, so neither does it lie, as not in the brain, so not in the tongue, but in the heart; it is not a notional knowledge of things to be believed; nor is it saying that a man believes; but it is heart work, a believing with all the heart; such a faith in which all the powers of the soul, the understanding, will, and affections, are concerned, it is a seeing of the Son, a beholding of the glory, fulness, suitableness, ability, and willingness of Christ as a Saviour, with the eye of the understanding spiritually enlightened; it is a going out of the soul to Christ, in various acts, such as venturing into his presence, prostrating itself at his feet, resolving if it perishes it will perish there; a giving up itself unto him, determining it will have no other Saviour, leaning and relying on him, and living upon him; which faith works by love to Christ, moves the affections, stirs up the desires of the soul to his name, and endears him and all that belong to him to it. The use of this grace is, "unto righteousness"; it is not instead of one, for faith is not our righteousness; nor is it in order to work out one, for this grace puts a soul on renouncing its own righteousness; but its use is to receive one, even the righteousness of Christ, which when it spies, it admires, receives, lays hold on, and rejoices in looking on itself as righteous through this righteousness, and so has peace with God through Christ: and with the mouth confession is made unto salvation. This is to be understood not of confession of sin, though that is proper and requisite to be made, both with respect to the participation, and enjoyment of salvation, particularly pardoning grace and mercy, and to an admission to Gospel ordinances; but of confession of Christ, as appears from the preceding verse, which lies in a frank and open acknowledgment of what Christ is in himself, as that he is truly and properly God, the Son of God, the true Messiah, the Mediator between God and man, and the only Saviour of lost sinners, and of our faith in him, with respect to ourselves, to our pardon, justification, acceptance and salvation in him and through him; in ascribing the whole of our salvation to him, and giving him the glory of it; in declaring to the churches of Christ what he has done for our souls, and in subjecting ourselves to his ordinances. This confession must be made both by words and facts, must be open, visible, and before men; and also real, hearty, and sincere, the words of the mouth agreeing with the experience of the heart; and such a good profession made before God, angels, and men, highly becomes all that believe with the heart. This was the practice of the primitive saints; yea, all nations own, acknowledge, and profess the God they worship; and should not we confess our God, Saviour and Redeemer? Christ himself confessed a good confession before Pontius Pilate, and is the Apostle and High Priest of our profession. So to do, makes both for the glory of God, and for our own real good and advantage. Yea, it is "unto salvation"; not as a cause of it, for Christ alone is the author of eternal salvation; but a sincere and well made confession of Christ points out to all that know us where and from whom we expect to have salvation; it is what lies in the way, and is to be taken up by all that believe in Christ, and to be held fast without wavering until we receive the end of our faith, even the salvation of our souls.”
Source
1832
A.D.
Adam Clarke Methodist
1762–1832
“For with the heart man believeth, etc. - And be sincere in this: for with the heart, duly affected with a sense of guilt, and of the sufficiency of the sacrifice which Christ has offered, man believeth unto righteousness, believeth to receive justification; for this is the proper meaning of the term here, and in many other parts of this epistle; and with the mouth confession is made unto salvation. He who believes aright in Christ Jesus will receive such a full conviction of the truth, and such an evidence of his redemption, that his mouth will boldly confess his obligation to his Redeemer, and the blessed persuasion he has of the remission of all his sins through the blood of the cross. One grand object of the apostle is to show the simplicity of the Gospel scheme of salvation; and at the same time, its great efficacy, it is simple, and very unlike the law, which was full of rites, ordinances, ceremonies, etc., each of which required to be perfectly fulfilled: and yet, after all, even those who had the utmost zeal for God, and, as conscientiously as possible, observed all the precepts of the law, had not attained to justification nor peace of conscience. Whereas both Jews and Gentiles, who had believed on the Lord Jesus according to the simple declarations of the Gospel, were freely justified from all things from which they could not be justified by the law of Moses: and they had the witness in themselves that they were passed from death to life.”
Source
1871
A.D.
1871
“For with the heart man believeth unto--justifying righteousness; and with the mouth confession is made unto salvation--This confession of Christ's name, especially in times of persecution, and whenever obloquy is attached to the Christian profession, is an indispensable test of discipleship.”
Modern · 1953 →

The in-app commentary runs from the Fathers to the early-modern record, then stops — that's where the public-domain sources end, not where the reading does. For the modern reading, follow the sources directly.