The interpretation timeline
Romans 16:21 Douay-Rheims

Timothy, my fellow labourer, saluteth you, and Lucius, and Jason, and Sosipater, my kinsmen.

A.D. 407 – 1871 7 witnesses

Patristic

before A.D. 750
date
unknown
c. A.D. 380
“Rough the whole world, and have left to you the bishops and to the rest of the priests this very Catholic doctrine worthily and righteously, as a memorial or confirmation to those who have believed in God; and we have sent it by our fellow-minister Clement, our most faithful and intimate son in the Lord, together with Barnabas, and Timothy our most dearly beloved son, and the genuine Mark, together with whom we recommend to you also Titus and Luke, and Jason and Lucius, and Sosipater.”
Source
407
A.D.
John Chrysostom Patristic
A.D. 347–407
“"Timotheus my work-fellow saluteth you." Observe the customary encomiums again. "And Lucius, and Jason, and Sosipater my kinsmen." This Jason Luke also mentions, and sets before us his manliness also, when he says, that "they drew" him "to the rulers of the city, crying," etc. And it is likely that the others too were men of note. For he does not mention relations barely, unless they were also like him in religiousness.”
Source

Scholastic

c. 1100 – 1500
1273
A.D.
Thomas Aquinas Catholic
1225–1274
“After the Apostle has enjoined whom they should greet, he here shows them whom they ought to avoid. And concerning this he does three things. First, he teaches whom they ought to avoid; second, he assigns the reason, at the words for such men, etc.; third, he promises them divine help for accomplishing this, at the words and the God of peace, etc. And because those whom he wished to be avoided proceeded fraudulently, deceiving under the appearance of piety, according to that word of Matthew 7:15: they come to you in sheep's clothing, but inwardly they are ravening wolves, therefore, first, he leads them to exercise caution, saying now I beseech you, brethren, to mark them which cause dissensions and offenses contrary to the doctrine which you have learned. Here, first, it should be considered that "to observe" is nothing other than to consider diligently, which indeed is sometimes taken in a good sense, sometimes in a bad sense. It is taken in a bad sense when someone diligently considers the condition and course of another in order to harm him, according to that word of Psalm 36:12: the sinner shall observe the just man, and shall gnash upon him with his teeth. And in Luke 14:1 it is said: and they watched him. It is taken in a good sense, in one way, when someone considers the precepts of God in order to do them. Exodus 23:21: observe therefore and hear his voice. In another way, when someone diligently considers good men in order to imitate them, according to that word of Philippians 3:17: be followers of me, brethren, and mark them which walk so, as you have us for a pattern. Third, evil men are observed in order to be avoided, and it is taken in this sense here. For there were certain men converted to the faith from among the Jews, who preached that the precepts of the law were to be observed, and from this, first, dissensions and sects followed in the Church, while some of them adhered to the error and others persisted in the true faith. Galatians 5:20: dissensions, sects, etc. Second, offenses and scandals followed, of which it was treated above in chapter 14, while some judged others and others despised others — these are the ones who cause dissensions and offenses. Isaiah 57:14: take away the stumbling-blocks out of the way of my people. Now he says contrary to the doctrine which you have learned from the true apostles of Christ, in order to show that such dissensions and scandals arose from the falsity of their teaching. Galatians 1:9: if any man preach any other gospel unto you than that which you have received, let him be anathema. Second, he warns that, once recognized, they should be avoided, saying and avoid them, that is, flee their doctrine and their company. Psalm 118:115: depart from me, you malignant ones, and I will search the commandments of my God. Then when he says for such men, etc., he assigns two reasons for what he had said, of which the first is taken from the side of those whom he wishes to be avoided. And first he describes their intention, saying for such men do not serve our Lord Christ, but their own belly. For they did not preach for the glory of Christ, but for gain, so as to fill their own belly. Philippians 3:18: many walk, of whom I have told you often, and now tell you even weeping, that they are the enemies of the cross of Christ, whose God is their belly. Second, he describes their deception, saying and by good words and fair speeches deceive the hearts of the innocent, that is, of the simple and unlearned. Proverbs 14:15: the innocent believeth every word. By good words, in which they pretend to sanctity, according to that word of Psalm 27:3: who speak peace with their neighbor, but evils are in their hearts. And fair speeches, namely by which they bless and flatter those who follow them. Isaiah 3:12: O my people, they that call thee blessed, the same deceive thee. Malachi 2:2: I will curse your blessings. He assigns the second reason from the condition of the Romans, who showed themselves ready to follow after both good and evil. Hence, first, he commends them for their readiness for good, saying for your obedience, by which you readily obeyed the faith, is come abroad unto all men, because of the dominion which the Romans then held over the other nations. Hence what was done by the Romans was readily spread abroad to others. Above, in chapter 1:8: your faith is spoken of throughout the whole world. I am glad therefore on your behalf, namely because you have obeyed the faith, and this in charity, of which it is said in 1 Corinthians 13:6, that it rejoiceth not in iniquity, but rejoiceth with the truth. Second, he makes them cautious against evil, saying but yet I would have you wise unto that which is good, namely that you cleave to that which is good — 1 Thessalonians, the last chapter: hold fast that which is good — and simple concerning evil, namely lest through some simplicity you decline toward evil, so that your simplicity may be such that you deceive no one unto evil. Matthew 10:16: be ye wise as serpents, and simple as doves. Conversely, of certain men it is said in Jeremiah 4:22: they are wise to do evil, but to do good they have no knowledge. Then when he says and the God of peace, etc., he promises them divine help against such deceivers. And first the promise is set down, when he says and the God of peace, that is, its author, who hates the dissensions that these men cause, shall bruise Satan, that is, the Devil who through these pseudo-apostles strives to deceive you, under your feet, because indeed you will conquer him through your wisdom. And this shall happen shortly, namely at my coming. Luke 10:19: behold, I give unto you power to tread on serpents and scorpions, and over all the power of the enemy. Malachi, the last chapter: you shall tread down the wicked, when they shall be as ashes under the sole of your feet. Second, the prayer for obtaining this is set down, when he says the grace of our Lord Jesus Christ be with you, which indeed suffices to protect you. 2 Corinthians 12:9: my grace is sufficient for thee. Then when he says Timothy my workfellow saluteth you, etc., he greets them on behalf of others, saying Timothy my workfellow saluteth you, namely in the preaching of the Gospel. 1 Corinthians 4:17: I have sent unto you Timotheus, who is my beloved son, and faithful, etc. He adds, moreover, and Lucius, and Jason, and Sosipater, my kinsmen, who were Jews, greet you, namely. Now there was a certain notary of Paul named Tertius, to whom Paul granted that he should greet the Romans in his own person. Hence it is added I Tertius, who wrote this epistle, salute you in the Lord. Then he says Gaius mine host saluteth you, to whom the third canonical epistle of John is addressed, in which he is commended for the charity which he showed to the saints. And of the whole church, namely which was gathered in his house, or which was in that province. Then he says Erastus the chamberlain of the city saluteth you, namely he who kept the common chest, that is, the common revenues of the city, and Quartus a brother, that is, a believer, by name Quartus. Then he greets them on his own behalf, saying the grace of our Lord Jesus Christ be with you all. Amen. And he ends the epistle with an act of thanksgiving, saying now to him, namely to God who is the Trinity, that is of power to establish you — 1 Peter, the last chapter: after that ye have suffered a while, he himself shall perfect, confirm, and establish you — and this in the faith which is according to my Gospel, that is, according to the Gospel which I preach. 1 Corinthians 15:11: whether it were I or they, so we preach, and so ye believed. And also according to the preaching of Jesus Christ, who first preached the Gospel, according to that word of Hebrews 2:3: which at the first began to be spoken by the Lord. Hence it is said in Matthew 4:23, that Jesus went about preaching the gospel of the kingdom. Now it is added, according to the revelation of the mystery, that is, of the secret, which indeed can be referred to what he had said above, according to my Gospel; or because in the Gospel itself the secret of the divine incarnation is revealed, according to that word above in chapter 1:17: the righteousness of God is revealed therein; or because to the Apostle himself the Gospel was revealed. 1 Corinthians 2:10: but unto us God hath revealed them by his Spirit. Concerning this secret it is said in Isaiah 24:16: my secret to myself. Or this may better be referred to what he had said, to establish, as if he were saying: God can establish you in my Gospel and preaching, and this according to the revelation of the mystery, that is, of the secret, namely concerning the conversion of the Gentiles, as is found in Ephesians 3:8 and following: unto me, who am less than the least of all saints, is this grace given, that I should preach among the Gentiles, and make all men see what is the dispensation of the mystery, etc. Hence he also adds since the world began, because indeed it was hidden among men that the Gentiles were to be converted to the faith. Now he calls these times eternal as if long-enduring, because from the beginning of the world this was hidden, as also is said in Psalm 75:4: thou, enlightening wonderfully from the everlasting mountains. And it can be said that the eternal times are called eternity itself, of which it is said in Isaiah 57:15: the high and eminent one, inhabiting eternity, so that just as the simple essence of God is described by a certain likeness through corporeal dimensions, according to that word of Job 11:9: the measure thereof is longer than the earth, and broader than the sea, so also his simple eternity is designated through eternal times, insofar as it contains all times. Now he adds that, namely the mystery, is now made manifest, concerning the conversion of the Gentiles, by the scriptures of the prophets, that is, according as the prophets foretold, as was made clear above in chapter 15. Hence in Ephesians 3:5 and following it is said: which in other ages was not made known unto the sons of men, as it is now revealed unto his holy apostles and prophets by the Spirit, that the Gentiles should be fellow-heirs, etc. Now it is made manifest through the fulfillment of the work by the command of God. Hence according to the commandment of the everlasting God, who indeed by his eternal purpose does in time the things which he wills, which command of God indeed is made known to all nations for the obedience of faith, that is, that all nations may obey the faith. Above, in chapter 1:5: for obedience to the faith among all nations. But if we speak of the mystery of the incarnation, the text is to be construed thus: of the mystery, I say, kept secret since the world began, because before it was not so manifest. Which mystery, I say, is now made manifest by the scriptures of the prophets, who foretold this according to the commandment of the everlasting God, who willed the mystery of the incarnation to be made manifest, and this for the obedience of faith among all nations. Of the mystery, I say, although kept secret among men, yet known only to God who is wise, because he alone knew this, and those to whom he willed to reveal it, because, as it is said in 1 Corinthians 2:11: the things of God knoweth no man, but the Spirit of God. Or it can be understood of him who alone is wise, namely by essence, as is said in Matthew 19:17 and Mark 10:18: none is good, save one, that is, God. Nor is the Son excluded by this, because the perfection of the whole Trinity is the same, just as, conversely, it is said: no man knoweth the Father, save the Son, Matthew 11:27 — the Father is not excluded from knowledge of himself. Now he adds by Jesus Christ; which is not to be understood in this sense, that God the Father is wise through Jesus Christ, because since for God to be wise is the same as to be, it would follow that the Father exists through the Son, which is unfitting; but this is to be referred to what he had said above: is now made manifest, namely through Jesus Christ. To whom, that is, to Jesus Christ, be honor and glory, through the reverence of the whole creature, according to that word of Philippians 2:10: at the name of Jesus every knee should bow. And glory, namely as to the fullness of his divinity, just as it is added there: and every tongue should confess that the Lord Jesus Christ is in the glory of God the Father. And this not for a time, but for ever, world without end. Hebrews, the last chapter: Jesus Christ, the same yesterday, and today, and forever. He adds, moreover, for the confirmation of the truth: Amen. Or it can be construed thus: known only to the wise God, to whom, through Jesus Christ, is glory — who glorified God, according to that word of John 17:4: I have glorified thee on the earth. Now it should be noted that this construction is defective, and is to be supplied thus: to him who is able, etc., be honor and glory through Jesus Christ, to whom is honor and glory. But if the word "to whom" is not there, the construction will be straightforward.”

Post-Reformation

c. 1650 – 1900
1714
A.D.
Matthew Henry Reformed
1662–1714
“As the Apostle had before sent his own salutations to many of this church, and that of the churches round him to them all, he here adds an affectionate remembrance of them from some particular persons who were now with him, the better to promote acquaintance and fellowship among distant saints, and that the subscribing of these worthy names, known to them, might the more recommend this epistle. He mentions, 1. Some that were his particular friends, and probably known to the Roman Christians: Timotheus my work-fellow. Paul sometimes calls Timothy his son, as an inferior; but here he styles him his work-fellow, as one equal with him, such a respect does he put upon him: and Lucius, probably Lucius of Cyrene, a noted man in the church of Antioch (Act 13:1), as Jason was at Thessalonica, where he suffered for entertaining Paul (Act 17:5, Act 17:6): and Sosipater, supposed to be the same with Sopater of Berea, mentioned Act 20:4. These Paul calls his kinsmen; not only more largely, as they were Jews, but as they were in blood or affinity nearly allied to him. It seems, Paul was of a good family, that he met with so many of his kindred in several places. It is a very great comfort to see the holiness and usefulness of our kindred. 2. One that was Paul's amanuensis (Rom 16:22): I Tertius, who wrote this epistle. Paul made use of a scribe, not out of state nor idleness, but because he wrote a bad hand, which was not very legible, which he excuses, when he writes to the Galatians with his own hand (Gal 6:11): pēlikois grammasi - with what kind of letters. Perhaps this Tertius was the same with Silas; for Silas (as some think) signifies the third in Hebrew, as Tertius in Latin. Tertius either wrote as Paul dictated, or transcribed it fairly over out of Paul's foul copy. The least piece of service done to the church, and the ministers of the church, shall not pass without a remembrance and a recompence. It was an honour to Tertius that he had a hand, though but as a scribe, in writing this epistle. 3. Some others that were of note among the Christians (Rom 16:23): Gaius my host. It is uncertain whether this was Gaius of Derbe (Act 20:4), or Gaius of Macedonia (Act 19:29), or rather Gaius of Corinth (Co1 1:14), and whether any of these was he to whom John wrote his third epistle. However, Paul commends him for his great hospitality; not only my host, but of the whole church - one that entertained them all as there was occasion, opened his doors to their church-meetings, and eased the rest of the church by his readiness to treat all Christian stranger that came to them. Erastus, the chamberlain of the city is another; he means the city of Corinth, whence this epistle was dated. It seems he was a person of honour and account, one in public place, steward or treasurer. Not many mighty, not many noble, are called, but some are. His estate, and honour, and employment, did not take him off from attending on Paul and laying out himself for the good of the church, it should seem, in the work of the ministry; for he is joined with Timothy (Act 19:22), and is mentioned Ti2 4:20. It was no disparagement to the chamberlain of the city to be a preacher of the gospel of Christ. Quartus is likewise mentioned, and called a brother; for as one is our Father, even Christ, so all we are brethren.”
Source
1771
A.D.
John Gill Reformed
1697–1771
“I Tertius, who wrote this epistle,.... This name is a Latin one, and perhaps the person might be a Roman, for the names Secundus, Tertius, Quartus, Quintus, &c. were common with the Romans; unless it may be thought, as it is by some, that this man was the same with Silas, who was a constant companion of the apostle; and the Hebrew word is the same as Tertius; he also is numbered among the seventy disciples, and said to be bishop of Iconium; See Gill on Luk 10:1. Whosoever he was, it is certain he was an amanuensis of the apostle, who wrote this letter, either from the apostle's notes, or from his mouth. Salute you in the Lord. Some connect this phrase, "in the Lord", with the other, "wrote this epistle", and make the sense to be that he wrote this epistle for the Lord's sake, for his honour and glory; which he might do, though he wrote it not by inspiration, being only scribe to the apostle; but it is better connected with the word "salute", and the sense is, that his salutation was not a mere form, nor only concerned their temporal good, but their spiritual welfare; that he wished them well in the Lord, that they might have much communion with him, and larger measures of grace from him.”
Source
1832
A.D.
Adam Clarke Methodist
1762–1832
“Timotheus my workfellow - This is on all hands allowed to be the same Timothy to whom St. Paul directs the two epistles which are still extant. See some account of him in the notes on Act 16:1 (note), etc. Lucius - This was probably Luke the evangelist, and writer of the book called The Acts of the Apostles. For a short account of him see the Preface to that book. Jason - It is likely that this is the same person mentioned Act 17:7, who at Thessalonica received the apostles into his house, and befriended them at the risk both of his property and life. Sosipater - He was a Berean, the son of one Pyrrhus, a Jew, by birth, and accompanied St. Paul from Greece into Asia, and probably into Judea. See Act 20:4.”
Source
1871
A.D.
1871
“Timotheus, my work-fellow--"my fellow labourer"; see Act 16:1-5. The apostle mentions him here rather than in the opening address to this church, as he had not been at Rome [BENGEL]. and Lucius--not Luke, for the fuller form of "Lucas" is not "Lucius" but "Lucanus." The person meant seems to be "Lucius of Cyrene," who was among the "prophets and teachers" at Antioch with our apostle, before he was summoned into the missionary field (Act 13:1). and Jason--See Act 17:5. He had probably accompanied or followed the apostle from Thessalonica to Corinth. Sosipater--See Act 20:4.”
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.