The interpretation timeline
Colossians 4:14 Douay-Rheims

Luke, the most dear physician, saluteth you: and Demas.

A.D. 202 – 1871 6 witnesses

Patristic

before A.D. 750
202
A.D.
Irenaeus Patristic
c. A.D. 130–202
“That he was not merely a follower, but also a fellow-labourer of the apostles, but especially of Paul, Paul has himself declared also in the Epistles, saying: "Demas hath forsaken me, ... and is departed unto Thessalonica; Crescens to Galatia, Titus to Dalmatia. Only Luke is with me." From this he shows that he was always attached to and inseparable from him. And again he says, in the Epistle to the Colossians: "Luke, the beloved physician, greets you." But surely if Luke, who always preached in company with Paul, and is called by him "the beloved," and with him performed the work of an evangelist, and was entrusted to hand down to us a Gospel, learned nothing different from him (Paul), as has been pointed out from his words, how can these men, who were never attached to Paul, boast that they have learned hidden and unspeakable mysteries?”
Source
407
A.D.
John Chrysostom Patristic
A.D. 347–407
“"Luke, the beloved physician, saluteth you." This is the Evangelist. It is not to lower this man that he placeth him after, but to raise the other, viz. Epaphroditus. It is probable that there were others called by this name. "And Demas," he says. After saying, "Luke, the physician, saluteth you," he added, "the beloved." And no small praise is this, but be beloved of Paul even great exceedingly.”
Source

Scholastic

c. 1100 – 1500
1272
A.D.
Thomas Aquinas Catholic
1225–1274
“Above he set down special teachings for each state of man; here he sets down what pertains to all, yet with respect to different persons. And first he shows how they ought to conduct themselves toward others; second, how others ought to conduct themselves toward them, at the place *what concerns me*, etc. Again, the first part is divided into two: first he shows how they ought to conduct themselves toward the apostle himself, their prelate; second, how toward others, especially unbelievers, at the place *in wisdom*. Concerning the first he does two things: first he urges them universally to pray; second, that they pray for him, at the place *praying*. Now prayer ought to have three qualities, namely that it be assiduous, grateful, and watchful. Assiduous — hence he says *being persistent in prayer*, that is, pray with perseverance. 1 Thess. 5:17: *pray without ceasing*, etc. Lk. 18:1: *it is necessary always to pray, and never to lose heart*. Likewise watchful, so that the mind not be weighed down; therefore it is added *watching*. 1 Pet. 4:7: *watch in prayers*, etc. Lk. 6:12: *he spent the night in prayer*, etc. Likewise grateful, that is, in thanksgiving — otherwise one does not merit new benefits, if one were ungrateful for those already received; hence there follows *in thanksgiving*. Phil. 4:6: *with thanksgiving*. 1 Thess. 5:18: *in all things give thanks*. Consequently he asks that they pray for him, saying *praying*, etc., because it is a debt that subjects pray for their prelates, since prelates guard them, and their good is the common good of all. 2 Thess. 3:1: *pray for us, that the word of the Lord may run*, etc. And this, that God may *open a door*, that is, the mouth, through which speech goes forth from the heart, and that God may give the grace of worthily uttering his word. In an opening, moreover, something great is signified. Matt. 5:2: *opening his mouth he taught them*, etc. And therefore he adds *to speak*. 1 Cor. 12:2: *it is the spirit that speaks mysteries*. And these I need, because on account of the word of Christ I suffer tribulations. Therefore it is to be prayed that I may be able to do so freely. 2 Tim. 2:9: *I labor even unto chains*. And in this manner, that he may *make it manifest*, that is, that he may disclose it, etc. There can be three impediments to the word: namely, either on account of fear, and therefore he says *in chains*; or on account of its loftiness, such that the hearers might not be able to understand it, and therefore he says *that I may make it manifest*; or on account of an unfitness of time or manner, and therefore he says *as I ought*. 1 Cor. 3:1: *I could not speak to you as to spiritual men*, etc. Lk. 12:42: *a faithful and prudent steward, whom*, etc. Consequently, when he says *in wisdom*, etc., he shows how they ought to conduct themselves toward outsiders, and first in conduct; second how in speech, at the place *your speech*. He says therefore *walk in wisdom* toward *those who are outside*, that is, unbelievers; *in wisdom*, that is, wisely. Wis. 7:28: *God loves no one except him who dwells with wisdom*, etc. And the reason for this is *redeeming*, etc. One redeems his own vexation when he gives up what is his by right, in order to avoid it. These men were being vexed by them; therefore he wants them to redeem it through wisdom. 1 Pet. 2:12: *having your conduct good among the Gentiles*, etc. Likewise he teaches, second, how they ought to conduct themselves in speaking. And first, that their speech be gracious; hence he says *let your speech always be in grace*. Ecclus. 6:5: *a gracious tongue abounds in a good man*. Second, that it be discreet; hence he says *seasoned with salt*. By salt is understood discretion: for through it every food that is seasoned is made savory, so every action without discretion is unsavory and disordered. Matt. 9: *have salt in yourselves, and have peace among yourselves*. And this *that you may know*, etc.: for one must answer the wise in one way, the foolish in another. Prov. ch. 26:4: *answer not a fool according to his folly, lest you become like him*, etc. 1 Pet. 3:15: *always ready to give satisfaction to everyone who asks you a reason*, etc. Then, when he says *what concerns me*, etc., he shows what others do toward them; and first he shows what those whom he sends to them do toward them; second, what those remaining with the apostle do, at the place *greets*. Now he sends to them a delegate, whom he first describes in three ways: first from love, calling him *most beloved brother*, namely through charity, which makes a man more precious than gold. Is. 13:12: *a man shall be more precious than gold, and a human being more than refined gold*, etc. Likewise from faith, hence he says *faithful in ministry*. 1 Cor. 4:2: *here now it is required among stewards that one be found faithful*. Likewise from humility, hence he says *and fellow servant*, namely in the carrying out of the ministry; but *in the Lord*, because a prelate ought to seek the advantage of those over whom he is set, and the honor of God. But for what purpose is he sent? That he may know the state of his subjects. Gen. 37:14: *go and see whether all things are well with your brothers and the flocks, and bring me word again of what is being done*, etc. 1 Kings ch. 17:18: *you shall visit your brothers to see whether they are doing well, and learn with whom they are placed*. Likewise that he may console. Rom. 1:11: *for I desire to see you, that I may impart to you some spiritual grace to strengthen you*, that is, to be consoled together with you, etc. And the Lord, sent by the Father, came for this purpose. Is. 61:2: *that I might console all who mourn*, etc. Likewise he describes his companionship with Onesimus, *who all the things that are done here*, etc. And your affairs to me, that I may correct them, and mine to you, that you may have an example. Then, when he says *greets*, etc., he shows how they are greeted by those remaining with the apostle, and the text is sufficiently clear. *Concerning whom you have received*, etc. Acts 13:5 it is said that when Paul and Barnabas were traveling together, a certain John Mark joined himself to them in such a way that afterward he departed and later returned again. And Paul indeed was unwilling to receive him, but Barnabas was willing. And therefore Paul withdrew from Barnabas. And on account of this the apostle wrote to the Colossians concerning Mark, that they should not receive him; but now, because he had turned back, he writes that they should receive him: and this is *you have received*, etc. Or, the brother of Barnabas, concerning whom you have received from Barnabas, etc. And *Jesus who is called Justus*, who indeed was a man of holy conduct, and therefore is called Justus. *Who are of the circumcision*, sent to preach the Gospel of Christ. Phil. 1:18: *For what does it matter? Provided that in every way, whether by occasion or by truth, Christ is proclaimed*. And thus he sets down first the Gentiles, second the Jews. *Epaphras, who is from among you*, etc., because he was an Asian. And to this end they greet you, *that you may stand perfect*. Jas. 1:4: *that you may be perfect also*, etc. *Full*, etc., that is, in all things which pertain to the will of God. Likewise he mentions Luke, who was not born of the Jews, as it seems, because he was an Antiochene, a physician by trade, whom he names specially, because he was a man of good authority in the Church on account of the Gospel which he wrote while the apostle was still living. Then he says *greet*, etc., he shows whom they should greet, and first how others of another church; second how those who are of their own, at the place *and that which is of the Laodiceans* — from which it is gathered that he wrote other epistles, namely this one which is mentioned here, that is, to the Laodiceans, and another one to the Corinthians, besides the first and the second: for in the first epistle, ch. 5, he says: *I wrote to you in an epistle, that you should not associate with fornicators*, etc. But there is a twofold reason why they are not in the canon: because their authority was not established, since perhaps they had been corrupted, and had perished in the churches. Or because they contained nothing other than what these do. And *say to Archippus* — this man was their prelate, and he instructs that they admonish him, saying: *see*, etc. 2 Tim. 4:5: *fulfill your ministry*. And indeed he then fulfills his ministry when he does that for which he received it. But it seems that it does not pertain to a subject to admonish a prelate, Ex. 19:24. It must be said that to argue and reproach irreverently is forbidden, but to admonish charitably is permitted, as Paul did Peter, Gal. 2:11. But why did he not write to the prelate? Because the prelate exists for the sake of the Church, and not the reverse. *The salutation*, etc. It was the apostle's custom to have someone else write the whole epistle, but at the end he would put something in his own hand — 2 Thess., last chapter, where he says: *the salutation is by my own hand, Paul's* — the same also here, lest they be deceived. And he says *be mindful*, etc., because he was in chains at Rome: for Jas. 5:10: *take as an example, brothers, the outcome of hardship and of long-suffering and of labor and of patience, the prophets who spoke in the name of the Lord*, etc. Heb., last chapter: *remember your leaders who have spoken to you the word of God, and considering the outcome of their conduct, imitate their faith*. Finally, concluding, he wishes them good, saying *grace*, etc. Jn. 1:17: *grace and truth came through Jesus Christ*: to whom be praise and glory, now and forever. Amen.”

Post-Reformation

c. 1650 – 1900
1771
A.D.
John Gill Reformed
1697–1771
“Luke, the beloved physician,.... Luke the Evangelist, though some doubt it, is here intended, who was a constant companion of the apostle in his troubles, and went with him to Rome, as the Acts of the Apostles wrote by him show, and as from Ti2 4:11 it appears; so Jerom (n) calls the Evangelist Luke, the physician of Antioch, for from thence he was; and being converted by the Apostle Paul, as is very probable, though some make him to be one of the seventy disciples, he became of a physician of bodies, a physician of souls: some say (o) he was a scholar of Galen, the famous physician, and others that he was his sister's son; who having heard of Christ's miracles, set out with his master Galen for Judea, to know the truth of them, of which they doubted; Galen died by the way, Luke came to Christ, and being taught by him, became one of the seventy disciples. The apostle calls him "beloved", not on account of his profession, in which he might be useful to many, but as he was a brother in Christ, a minister of the Gospel, and a fellow labourer of his. This is the same person as Lucas, mentioned along with Demas, and others, as here, in Plm 1:24. The name perhaps is Roman, but was, however, well known among the Jews; for they say (p), the "witnesses that sign a divorce, and their names are as the names of strangers, what is to be done with it? there is none comes into our hands (is received) but "Lukus" and "Lus", and we allow it to be right:'' upon which the gloss says, because these were famous names: and Demas greet you; the same who, through the love of the present world, forsook the apostle, Ti2 4:10 which he did either after the writing of this epistle, or if before it, he was now returned again to him: his name seems to be the same with the Roman Dama, unless it should be a contraction of Demetrius, or rather of Demarchos; though the Jews make frequent mention of R. "Dimi", or "Demi", in their writings (q), which perhaps is the same name with this. (n) Catalog. Script. Eccles. p. 91. Vid. Nicephor. Hist. l. 2. c. 43. (o) Vid. Castell. Lex. Polyglott. col. 1894. (p) T. Bab. Gittin, fol. 11. 2. (q) T. Bab. Gittin, fol. 19. 2. Nazir, fol. 36. 1. Sota, fol. 43. 2. Bava Kama, fol. 43.”
Source
1832
A.D.
Adam Clarke Methodist
1762–1832
“Luke, the beloved physician - This is generally supposed to be the same with Luke the evangelist. See the preface to the notes on this gospel. Some, however, suppose them to be different persons; because, where it is evident that Luke the evangelist is meant, he never has more than his simple name Luke; and because the apostle is supposed to intend a different person here, he adds, ὁ ιατρος ὁ αγαπητος, the beloved physician. The word ιατρος signifies a healer, and must not be restricted to physician, in the sense in which we use that word; he was surgeon, physician, and dispenser of medicines, etc., for all these were frequently combined in the same person.”
Source
1871
A.D.
1871
“It is conjectured that Luke "the beloved physician" (the same as the Evangelist), may have first become connected with Paul in professionally attending on him in the sickness under which he labored in Phrygia and Galatia (in which latter place he was detained by sickness), in the early part of that journey wherein Luke first is found in his company (Act 16:10; compare Note, see on Gal 4:13). Thus the allusion to his medical profession is appropriate in writing to men of Phrygia. Luke ministered to Paul in his last imprisonment (Ti2 4:11). Demas--included among his "fellow laborers" (Plm 1:24), but afterwards a deserter from him through love of this world (Ti2 4:10). He alone has here no honorable or descriptive epithet attached to his name. Perhaps, already, his real character was betraying itself.”
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.