The interpretation timeline
Romans 2:29 Douay-Rheims

But he is a Jew, that is one inwardly; and the circumcision is that of the heart, in the spirit, not in the letter; whose praise is not of men, but of God.

A.D. 215 – 1832 7 witnesses

Patristic

before A.D. 750
215
A.D.
c. A.D. 150–215
“He impoverishes himself, in order that he may never overlook a brother who has been brought into affliction, through the perfection that is in love, especially if he know that he will bear want himself easier than his brother. He considers, accordingly, the other's pain his own grief; and if, by contributing from his own indigence in order to do good, he suffer any hardship, he does not fret at this, but augments his beneficence still more. For he possesses in its sincerity the faith which is exercised in reference to the affairs of life, and praises the Gospel in practice and contemplation. And, in truth, he wins his praise "not from men, but from God," by the performance of what the Lord has taught.”
Source
220
A.D.
Tertullian Patristic
c. A.D. 150–220
“Now it is quite within the purpose of the God of the law that circumcision should be that of the heart, not in the flesh; in the spirit, and not in the letter. Since this is the circumcision recommended by Jeremiah: "Circumcise (yourselves to the Lord, and take away) the foreskins of your heart; " and even of Moses: "Circumcise, therefore, the hardness of your heart," -the Spirit which circumcises the heart will proceed from Him who prescribed the letter also which clips the flesh; and "the Jew which is one inwardly" will be a subject of the self-same God as he also is who is "a Jew outwardly; " because the apostle would have preferred not to have mentioned a Jew at all, unless he were a servant of the God of the Jews.”
Source
367
A.D.
Hilary of Poitiers Patristic
c. A.D. 310–367
“The apostle testifies without any hesitation that those who walk according to the teaching of Christ—in the spirit, not in the letter—are the Israel of God.”
407
A.D.
John Chrysostom Patristic
A.D. 347–407
“"But he is a Jew which is one inwardly; and circumcision is that of the heart, in the spirit, and not in the letter." By saying this he sets aside all things bodily. For the circumcision is outwardly, and the sabbaths and the sacrifices and purifications: all of which he hints in a single word, when he says, "For he is not a Jew which is one outwardly." But since much was made of the circumcision, inasmuch as even the sabbath gave way to it (John vii. 22), he has good reason for aiming more especially against it. But when he has said "in the spirit" he thereafter paves the way for the conversation of the Church, and introduces the faith. For it too is in the heart and spirit and hath its praise of God. And how cometh he not to show that the Gentile which doeth aright is not inferior to the Jew which doeth aright, but that the Gentile which doeth aright is better than the Jew which breaketh the Law? It was that he might make the victory an undoubted one. For when this is agreed upon, of necessity the circumcision of the flesh is set aside, and the need of a good life is everywhere demonstrated. For the Greek is saved without these, but the Jew with these is yet punished, Judaism stands by doing nothing. And by Greek he again means not the idolatrous Greek, but the religous and virtuous, and free from all legal observances.”
Source
430
A.D.
Augustine of Hippo Patristic
A.D. 354–430
“This means that the law should be understood according to the Spirit, and not according to what the letter says. This pertains especially to those who have interpreted circumcision more according to the flesh than according to the Spirit.”

Scholastic

c. 1100 – 1500
1273
A.D.
Thomas Aquinas Catholic
1225–1274
“Having shown that doers of the law are justified even without being hearers, which pertained to the Gentiles, here he shows that hearers are not justified unless they are doers, which pertains to the Jews. First, therefore, he shows the prerogative of the Jews with respect to the reception of the law; second, he sets forth their defect with respect to the transgression of the law, at the place, "Thou therefore that teachest another." Now he sets forth their prerogative in a threefold way. First, with respect to the nation to which the law was given; second, with respect to the law, at "and restest in the law"; third, with respect to the effect or fruit of the law, at "and knowest his will." Now, with respect to the nation, he says, "But if thou art called a Jew," which is an honorable name, according to that word of Psalm 113:2: "Judea was made his sanctuary." John 4:22: "Salvation is of the Jews." Now they are called Jews, not from Judas Machabeus, as some say, perhaps on account of this, that Judas Machabeus gathered together and protected that nation while it existed in dispersion, according to that word of 1 Machabees 3:2ff.: "He fought the battles of Israel with gladness, and enlarged the glory of his people." For the name of the Jews is found before Judas Machabeus, according to that word of Esther 8:16: "To the Jews new light seemed to arise." And therefore it must be said that the Jews are named from Judah the patriarch, Genesis 49:8: "Judah, thee shall thy brethren praise." For when, in the time of Rehoboam, the ten tribes, separating themselves from his kingdom, worshipped the golden calf, they were led away into transmigration by the Assyrians, as is related in 1 Kings 17. Nor does Scripture make mention of their return, but rather the land remained occupied by foreigners, who afterward were called Samaritans. But the two tribes, namely of Judah and Benjamin, adhering to the kingdom of Rehoboam, persevered in the worship of God. And although they were led into the captivity of Babylon, afterward, nevertheless, through Cyrus king of the Persians they were brought back into their own land, as is said in 1 Esdras 1. And because the tribe of Judah was greater, that whole nation was named from it — and not only those who were of the tribe of Benjamin, but also those from the other tribes who, returning, joined themselves to them. Consequently, when he says "and restest in the law," he sets forth their prerogative with respect to the law. And first indeed, with respect to the law itself, when he says "and restest in the law," as it were made certain through it in what is to be believed and in what is to be done. For one who doubts in the intellect does not rest, but is drawn about on both sides; but he who receives the certainty of wisdom rests in mind. Wisdom 8:16: "Entering into my house, I shall rest myself with her." Second, with respect to the lawgiver, when he adds "and gloriest in God," that is, in the worship and knowledge of the one God. Jeremiah 9:24: "In this let him glory that glorieth, to know and to understand me." 1 Corinthians 1:31 and 2 Corinthians 10:17: "He that glorieth, let him glory in the Lord." Then, when he adds "and knowest," he sets forth their prerogative with respect to the fruit of the law: first, as it regards man with respect to himself; second, with respect to others, at "thou trustest." Now he sets forth a twofold fruit. The first indeed corresponding to the glory which they had concerning God, when he says "thou knowest his will," namely, what God wills us to do. Below, 12:2: "That you may prove what is the will of God." He sets forth the second fruit, which corresponds to one resting in the law of God, when he says "and approvest the more useful things," that is, thou knowest how to approve by choosing not only the evil from the good, but also the better from the less good. Whence a certain man asked, Matthew 22:36: "Which is the great commandment?" And this, instructed through the law. Psalm 33:12: "Blessed is the man whom thou shalt instruct, O Lord, and shalt teach him out of thy law." Consequently he sets forth the fruits with respect to others, who indeed stand in a threefold way with regard to the knowledge of the law. For some are established wholly in ignorance of the law. In one way indeed through a defect of natural intelligence, just as a man is also said to be bodily blind through a defect of the interior visive power. Isaiah 59:10: "We have groped for the wall like blind men." Now to men of this sort a man cannot furnish the light of knowledge, so that they themselves might be able to see through themselves what is to be done, but a man furnishes them guidance as to the blind, commanding them what they ought to do, although they do not know the reason of the commands — Job 29:15: "I was an eye to the blind" — of whom nevertheless it is said, Matthew 15:14: "They are blind, and leaders of the blind." In another way some are in ignorance through a defect of instruction, who are as it were in outer darkness, not illumined by teaching, to whom a wise man can furnish the light of instruction, that they may understand what is commanded; and this is what he says: "a light of them that are in darkness." Luke 1:79: "To enlighten them that sit in darkness." Second, however, he touches upon those who are on the way to arriving at knowledge, which they have not yet attained. And this, in one way, through a defect of full instruction. And this is what he says: "an instructor of the foolish," that is, of those who have not yet received wisdom, who are said to be instructed, as it were drawn out from rudeness, which is present in all from the beginning, when they are first instructed. Ecclesiasticus 7:25: "Hast thou children? Instruct them." In another way through a defect of age, as children are. And with respect to this he says: "a teacher of infants." Isaiah 33:18: "Where is the teacher of the little ones?" But the third are those who are already advanced in knowledge. And these need to be formed by the wise, so that they may hold the sayings of the wise in authority as a kind of rule or model. And with respect to this he says: "having the form of knowledge." 2 Timothy 1:13: "Hold the form of sound words which thou hast heard of me." And Philippians 3:17: "Observe them who walk so, as you have our model." Now it is necessary that those who are thus formed be instructed by the authority of their elders, that they may know what is handed down in the law, and therefore he says "of knowledge." Wisdom 10:10: "She gave him the knowledge of the saints." And also that they may know what is the true understanding of those things which are handed down in the law. And with respect to this he says "of truth." Psalm 42:3: "Send forth thy light and thy truth." Then, when he says "Thou therefore that teachest another," he shows their defect according to the transgression of the law. And, first, of man toward himself, when he says "Thou therefore that teachest another" — directing him to the good — "teachest not thyself" — directing. And this can be read either as a question, as it were with a certain indignation, or gently, as it were asserting their malice; and it is similar in what follows. Job 4:3: "Behold thou hast taught many," and below: "but now the stroke is come upon thee, and thou hast fainted." Second, he touches upon the defect with respect to one's neighbor. First indeed, with respect to goods which are taken away by theft, when he says: "Thou that preachest that men should not steal, stealest?" Isaiah 1:23: "Thy princes are faithless, companions of thieves." Second, with respect to the joined person, who is polluted through adultery. And with respect to this he says: "Thou that teachest men not to commit adultery, committest adultery?" Hosea 7:4: "They are all adulterers, like an oven." Jeremiah 5:8: "Every one after his neighbor's wife." Third, however, he shows their defect by comparison of them to God, and, first indeed, with respect to this, that they sinned against his worship. And with respect to this he says: "Thou that abhorrest idols" — knowing, namely, from the precept of the law that they are not to be worshipped — "committest sacrilege," namely, by abusing those things which pertain to divine worship. Which indeed they did first in the state of the law, Malachi 1:12: "You say: The table of the Lord is defiled," and afterward by blaspheming Christ, Matthew 12:24: "By Beelzebub the prince," etc. Second, with respect to glory itself, when he says: "Thou that gloriest in the law, through transgression of the law dishonorest God." For just as the observance of the law in good works is an occasion for those who see it to honor God, so also the transgression of the law through evil works is an occasion for those who see it to blaspheme. 1 Peter 2:12: "That, considering you by your good works, they may glorify God." But on the contrary it is said, 1 Timothy 6:1: "Whosoever are servants under the yoke, let them count their masters worthy of all honor, lest the name of the Lord and his doctrine be blasphemed." And therefore in Psalm 118:158 it is said: "I beheld the transgressors, and I pined away." And for this he brings in an authority, adding: "For the name of God through you is blasphemed among the Gentiles" — because, namely, the Gentiles, seeing the evil manner of life of the Jews, reckoned this to come from the evil instruction of the law handed down by God. Now he says "as it is written," namely Isaiah 52:5: "Its rulers act unjustly, and continually, all the day long, my name is blasphemed"; and Ezekiel 36:22, according to another text, where our own reads thus: "I do it not for your sake, O house of Israel, but for my holy name's sake, which you have profaned among the Gentiles." Then, when he says "circumcision," he shows that neither does circumcision suffice for salvation, for the same reason that neither does the law, because, namely, the observance of the law avails without circumcision, whereas circumcision without it, however, does not profit, as has been said above. And concerning this he does three things. First he compares circumcision to circumcised Jews; second, to uncircumcised Gentiles, at "if therefore the uncircumcision"; third he clarifies what he had said, at "for it is not he that is a Jew outwardly." Concerning the first he does two things. First he shows how circumcision profits; second, how it does not profit, at "but if thou be a transgressor," etc. He says therefore first: "Circumcision indeed profits" with respect to the remission of original sin, whence it is said, Genesis 17:14: "The male whose flesh of his foreskin is circumcised," etc. But "to thee," as an adult, it profits in the end only "if thou observe the law," just as profession profits religious, if they observe the rule. For circumcision was, as it were, a certain profession, obliging men to the observance of the law. Galatians 5:3: "I testify to every man circumcising himself, that he is a debtor," etc. Now what the Apostle said — "If you be circumcised, Christ shall profit you nothing" — he speaks with respect to the time after the grace of the Gospel was published; but here he speaks with respect to the time before the passion of Christ, in which circumcision still had its standing. Second, at "but if thou be a transgressor," he shows how circumcision does not profit, saying: "If thou, O Jew, being an adult, art a transgressor of the law, thy circumcision is made uncircumcision," that is, it avails thee no more than uncircumcision, because thou dost not keep what by circumcision thou dost profess — Jeremiah 9:26: "All the nations have uncircumcision, but the house of Israel are uncircumcised in heart" — indeed, from this they are the more guilty, because they do not keep what they promised. For "a foolish and faithless promise displeaseth," as is said in Ecclesiastes 5:3. Then, when he says "if therefore the uncircumcision," he compares circumcision to the Gentiles, and this in two ways. First indeed, with respect to this, that the Gentiles have its fruit by observing the law. Whence he says: if circumcision profits along with the observance of the law, but not without it, therefore, "if the uncircumcision," that is, the uncircumcised Gentile, "keep the justices of the law," that is, the just precepts of the law — Psalm 118:86: "All thy commandments are truth" — "shall not his uncircumcision be reputed for circumcision?" As if he were to say: he will have the fruit of true circumcision. For to this end a man is outwardly circumcised in the flesh, that he may, namely, circumcise himself in the heart. Jeremiah 4:4: "Be circumcised to the Lord, and take away the foreskins of your hearts." Second, at "and shall judge," etc., he compares circumcision to the Gentile, showing that on account of the observance of the law he is to be preferred to the Jew. Whence he says: "and the uncircumcision," that is, the uncircumcised Gentile, "fulfilling," that is, accomplishing the commandments of the law, "by nature," that is, through natural reason — as was said above, that they do by nature the things that are of the law — "shall judge," by comparison, "thee," namely the circumcised Jew, "who art a transgressor of the law," by transgressing its precepts, "by the letter," that is, having the law written in letters, "and circumcision," namely, of the flesh. Whence concerning this judgment of comparison it is said, Matthew 12:41: "The men of Nineveh," etc. Then, when he says "for it is not he that is a Jew outwardly," etc., he assigns the reason for what has been said. And first he sets forth the reason; second he proves it, at "whose praise." Concerning the first he does two things. First he assigns the reason why circumcision or Judaism without the observance of the law does not profit; second he assigns the reason why the observance of the law profits without Judaism and circumcision, at "but he that is a Jew in secret." He says therefore that the circumcision of one who transgresses the law is for this reason uncircumcision, and is judged by the uncircumcision which keeps the law, because he is not a true Jew who is a Jew "outwardly," according to carnal generation. Below, 9:6: "For not all who are of the circumcision are Israel, these are Israelites, but they who are children of the promise." And likewise also that is not true circumcision which is manifest in the flesh. For that is a sign, as it is said, Genesis 17:11: "You shall circumcise the flesh of your foreskin, that it may be for a sign of the covenant." But it is not a true sign, unless the thing signified correspond to it. Whence if any Jew were a transgressor of the covenant, his circumcision would not be true, and therefore it is reputed as uncircumcision. Then, when he says "but he that is a Jew in secret," he assigns the reason why the uncircumcision of one who keeps the law is reputed as circumcision and judges carnal circumcision; because, namely, he is truly a Jew who is a Jew "in secret," that is, who holds in the affection of his heart the commandments of the law, which the Jews profess. Matthew 6:6: "Thy Father who seeth in secret," etc. And likewise that is true circumcision which is "of the heart, in the spirit," that is, made through the spirit, by which superfluous thoughts are cut off from the heart. Or "in the spirit," that is, through the spiritual understanding of the law, not the literal. Philippians 3:3: "We are the circumcision, who serve God in the spirit." Then, when he says "whose praise," etc., he proves the reason already given. For it is manifest that in all things the divine judgment is to be preferred to the human. Now those things which appear outwardly, whether it be Judaism or circumcision, are praised by men, but those things which are in secret are praised according to the divine judgment, because, as it is said, 1 Kings 16:7: "Man seeth those things that appear, but God beholdeth the heart," etc. Whence it remains that interior Judaism and circumcision prevails over the exterior. And this is what he says: "whose" — namely, of the interior circumcision — "praise is not of men, but of God." 2 Corinthians 10:18: "For not he who commendeth himself," etc.”

Post-Reformation

c. 1650 – 1900
1832
A.D.
Adam Clarke Methodist
1762–1832
“But he is a Jew - A true member of the Church of God. Which is one inwardly - Who has his heart purified, according to what God has uniformly prescribed by his prophets; see above: for circumcision is of the heart, in the spirit, εν πνευματι by the Spirit of God, who is the author of all spiritual affections and holy purposes: or, every thing here is to be understood spiritually, and not literally; for without holiness none can please God, and without holiness none can see him. Whose praise is not of men - It has, with great probability, been conjectured that the apostle may here refer to the signification of the name Jew, or Judah, יהודה Yehudah, Praise, from ידה Yadah, he Praised. Such a one is a true Israelite, who walks in a conformity to the spirit of his religion: his countrymen may praise him because he is a steady professor of the Jewish faith; but God praises him, because he has entered into the spirit and design of the covenant made with Abraham, and has got the end of his faith, the salvation of his soul. Sentiments like these, on the same subject, may be found in the ancient Jewish writers. Rabbi Lipman gives the opinion of their most ancient and pure writers in these words: - "A certain Christian mocked us, saying, 'Women, who cannot be circumcised, cannot be reckoned among Jews.' Such persons are ignorant that faith does not consist in circumcision, but in the heart. He who has not genuine faith is not a partaker of the Jewish circumcision; but he who has genuine faith is a Jew, although not circumcised." Nizzachon, Num. 21, p. 19. It is a curious maxim of the Talmudists, That the Jews sit in the inmost recesses of the heart. Nidda, fol. 20, 2. This is exactly the sentiment of St. Paul: Circumcision is of the heart, in the spirit. In short, common sense, as well as their law and their prophets, taught every considerate man among them that God could be pleased with their rites and external performances no farther than they led to holiness of heart and righteousness of life. 1. What the apostle says, in the preceding chapter, concerning the Gentiles doing by nature the things contained in the law, if properly considered, would lead certain persons from forming erroneous judgments concerning the Divine dispensations. We are not to suppose that God is not to be found where his written word does not appear; nor that the salvation of the nations yet unblessed with the light of the Gospel is impossible. God has never confined himself to any one particular way of communicating his salvation, any more than he has confined his saving grace to one people. His word is an indescribable blessing; but that word becomes effectual to salvation when accompanied by the power of the Holy Spirit. It was that Spirit which gave the word originally; and that same Spirit can speak without this word. It is through his influence alone that the Gentiles do the things contained in his own law; and it is not to be wondered at that the work is the same, both in the law and in the heart, when it has proceeded from the same Spirit. 2. God therefore will judge all nations according to the use and abuse they have made of this word, whether it was written in the heart, or written on tables of stone. 3. As he is no respecter of persons, all nations are equally dear to him; and he has granted and will grant to them such discoveries of himself as have been and will be sufficient for their salvation. 4. His Word is an infinite blessing; and he has given it to one people that they may be the means of conveying it to another. Europe, and especially Christian Europe, has got the Bible; and God requires Europe to send the Bible throughout the earth. If this be not done, through their neglect, the Gentile nations will not be destroyed by a merciful God; yet the Europeans will have a most solemn and awful account to render to their Judge, that they have hidden the heavenly light under their own bushel. Britain is shaking herself from the dust, and, by means of the British and Foreign Bible Society, is sending the holy Scriptures to every kingdom, and nation, and people, and tongue. The Gentiles are now learning from the written law more fully and savingly what the Spirit of God had before written on their hearts; and it seems as if the kingdom of God were now about to come with all-conquering power.”
Source
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.