The interpretation timeline
2 Corinthians 8:22 Douay-Rheims

And we have sent with them our brother also, whom we have often proved diligent in many things; but now much more diligent, with much confidence in you,

A.D. 407 – 1871 7 witnesses

Patristic

before A.D. 750
407
A.D.
John Chrysostom Patristic
A.D. 347–407
“"And we have sent with them our brother." Behold, again he adds yet another, and him also with an encomium; both his own judgment, and many other witnesses [to him]. "Whom," saith he, "we have many times proved earnest in many things, but now much more earnest." And having praised him from his own good works, he extols him also from his love towards them; and what he said of Titus, that "being very earnest he went forth of his own accord;" this he says of this person also, saying, "but now much more earnest;" laying up beforehand for them the seeds of [the proof of their] love toward the Corinthians.”
Source

Scholastic

c. 1100 – 1500
1272
A.D.
Thomas Aquinas Catholic
1225–1274
“After he has treated of the giving of the collections, here he consequently treats of the ministers through whom the collections are made. And concerning this he does two things. First he names them; second he commends them to the Corinthians, at "the showing therefore which is," etc. Concerning the first he does three things. For first he names Titus; second Barnabas, at "we have also sent with him the brother," etc.; third Apollo, at "we have sent with them," etc. Concerning Titus he commends two things, namely his solicitude and the sign of his solicitude, at "for indeed the exhortation," etc. He says therefore first: I have said, above, that I asked Titus to complete this grace concerning the gathering of alms, which is incumbent upon my solicitude by the ordination of the apostles, in which matter I also found him solicitous; and therefore I give thanks to God, who gave the same solicitude, which I have, for you, to be exhorted and advanced to works of mercy, in the heart of Titus; because he too is solicitous, just as I am, that he may complete this grace in you. Heb. 6:11: we desire each one of you to show the same solicitude, etc. Rom. 12:8: he who presides, in solicitude. Now the sign of this solicitude is that when I asked him, he himself consented to my exhortation. And therefore he says: for indeed he received the exhortation. And because he pursued what I asked, whence he says: but since he was more solicitous by his own will than by my exhortation, he set out to you; who nevertheless at first refused to come on account of your sins. Rom. 12:11: in solicitude, not slothful. Consequently, when he says "but we have sent," etc., he treats of the second minister. And concerning this he does two things. First he commends him; second he adds the reason why he sends such solemn messengers, at "avoiding," etc. This brother, according to some, is Luke, or according to others Barnabas, whom indeed he commends from three things: from fame, because his praise, namely Luke's, is in the Gospel written by him throughout all the Churches, because it has been approved by the apostles. Or whose praise, namely Barnabas's, is in the Gospel preached by him throughout all the Churches, because to the Jews and to the Gentiles. Whence it is said of Barnabas, Acts 11:24, that he was a good man, full of faith and the Holy Spirit. Likewise he commends him from his companionship, because he is not only famous, but has also been appointed by the Churches of Judea as a companion of my pilgrimage, that is, of my preaching, by which, as pilgrims, we go about the world. Above ch. 5:6: as long as we are in the body, we are pilgrims from God, etc. And this is true of Luke, because he was one of the seventy-two disciples, and a companion of Paul. Of Barnabas likewise, because through the Holy Spirit it is said, Acts 13:2: separate for me Barnabas and Paul unto the work, etc. And he was made a companion in this grace, namely of the collection of alms. Or in this grace, namely of preaching, of which it is said Eph. 3:8: but to me, the least of all the saints, etc. Likewise he commends him from office, because he is a minister of the grace which is ministered by us. 1 Cor. 4:1: so let a man esteem us. Above ch. 3:6: who also has made us fit, etc. Now this grace is ministered unto the glory of the Lord, that is, that our Lord may be glorified, namely from the alms given, from the conversion of very many peoples to our preaching, because, as it is said Prov. 14:28, in the multitude of the people, etc. Likewise it is ministered, that our will may be fulfilled, because we wish this to be done. And therefore he says: and our will, destined — that is, predestined by God, who predestined from eternity that we should have such a will. Consequently, when he says "avoiding," etc., he assigns the cause why he sends such solemn messengers. And first he assigns the reason for this; second he proves it, at "we provide therefore," etc. He says therefore: the reason why we send such solemn messengers is this: that you may know that a business of this kind is present to our heart. And therefore he says "avoiding this," namely lest anyone, etc., as if to say: that we might avoid the reproach which could be cast upon me by some, either of negligence, if I did not send diligent men, or of fraud, if I did not send trustworthy ones. And these were diligent and ready and trustworthy, because they were given by the Churches and chosen through the Holy Spirit. Above ch. 6:3: giving no offense to anyone, etc. Now he says "in this abundance," namely of alms or of the conversion of the Gentiles. 1 Pet. 4:10: each one, as he has received grace, unto one another, etc. And he proves this, saying "for we provide," etc., as if to say: I rightly say "avoiding," because we provide — that is, we ought to provide — good things, that is, that our works may be good not only before God, that we may please him, but also before men, that is, that they may appear good to them. And this he does, by carefully procuring and imitating the good. Rom. 12:9: cleaving to the good, etc. Consequently, when he says "but we have sent with them our brother also," etc., he treats of the third messenger, namely of Apollo. Where he does two things. First, he commends him for his solicitude, when he says "whom," namely Apollo, "we have often proved to be solicitous for your salvation; but now much more solicitous." For, as appears above, Apollo was the first who preached at Corinth after the apostle. 1 Cor. 3:6: I planted, Apollo watered. But this man, disturbed by their sin, withdrew, and set aside the solicitude which he had before had for them. But now, having heard of their conversion, he became more solicitous for their salvation than he had been before. Eph. 4:3: solicitous to keep the unity of the spirit, etc. Rom. 12:8: he who presides, in solicitude, etc. Second, he adds the cause of the solicitude which he took up, because Apollo trusted concerning you from those things which Titus said about you, commending you. Whence he says "with much confidence in you," whether on account of Titus who is my companion, and because he willingly came into the fellowship of Titus and Luke or Barnabas, and because he was induced to this by the apostles of the Churches which are in Judea. And therefore he says "or our brethren," the apostles of the Churches of Judea, namely they induced him to have solicitude for you. Which Churches indeed are "of the glory of Christ," that is, unto the glory of Christ. Consequently, when he says "the showing therefore which is," etc., he commends these messengers to the Corinthians, saying: because we have sent such men to you, therefore "the showing," etc., that is, show by deed, that you have charity toward them, and that I have truly commended you, and that I have truly gloried concerning you in the face of the Churches, to which I have come and to which I have preached. Or "in the face of all the Churches," because what you do to them will become known to all the Churches.”

Reformation

c. 1500 – 1650
1637
A.D.
1567–1637
“And we have sent with them our brother . Who this is is uncertain. Some, says Anselm, think that it is Apollos ; but they suspect only, for S. Paul neither names him nor describes him, but leaves the Corinthians to their personal knowledge of him. Upon the great confidence which I have in you . Having great confidence and hope that, as is right, they will be received honourably and lovingly by you, and also partly out of love and respect for Titus, who is my companion and fellow-helper. Hence Titus was now at Corinth, having been sent there by S. Paul to collect these alms and to transact other business. Maldonatus supplies the verb show , and makes the sentence run : “ Upon the great confidence that whatever love you show to Titus you will show to me, for he is my partner.” But there is no need to supply anything — the sense given above is clear enough without it”
Source

Post-Reformation

c. 1650 – 1900
1771
A.D.
John Gill Reformed
1697–1771
“Whether any do inquire of Titus,.... The apostle here sums up the characters of each of the above persons; as for Titus, he says, he is my partner; he had been his companion in his travels, a partner with him in preaching the Gospel, as well as in the troubles and persecutions he had met with; and was one with whom he had had sweet communion and fellowship: and fellow helper; or worker, concerning you; he had been a joint instrument with him, either in their conversion, or consolation, and correction; or for their edification and instruction, and setting things right, which had been out of order among them: or our brethren be inquired of; if their characters are asked after, as well as Titus's; by whom are meant not his fellow apostles, but the two brethren who were sent along with Titus; what may be truly said of them is, they are the messengers of the churches; they were chosen and sent forth by the churches, not only to preach the Gospel, but particularly to take care of the ministration to the poor saints. They were messengers appointed by the churches for this service, and were also appointed to the service of the churches; respect seems to be had to the public minister in the synagogues, who was called "the messenger of the congregation", or "church" (z); whose business was to take care about the reading of the law and the prophets, to pray in public, and also to preach if there was no other; so we read (a) also of , "the messengers of the sanhedrim"; who were sent at the proper time to reap the sheaf of the first fruits, and of others who swore the high priest before the day of atonement (b); and of , "the messengers of the commandment" (c); who went to hear the exposition (of the traditions) and visit the head of the captivity: and the glory of Christ: meaning either that the churches were the glory of Christ, in whom he is glorified, where his glory is seen, and his presence enjoyed; or rather the messengers of them, on whom the image of Christ was stamped, who faithfully performed the work of Christ, in all things sought his glory and not their own; and in and by whom his glory was displayed, and held forth to others. (z) T. Bab. Sota, fol. 37. 2. Tosephot Beracot, fol. 34. 1. Misn. Beracot, c. 5. sect. 5. (a) Misn. Menachot, c. 10. 3. (b) Misn. Yoma, c. 1. 5. (c) T. Bab. Succa, fol. 26. 1.”
Source
1832
A.D.
Adam Clarke Methodist
1762–1832
“We have sent with them - Titus and, probably, Luke, our brother, probably Apollos. Now much more diligent - Finding that I have the fullest confidence in your complete reformation and love to me, he engages in this business with alacrity, and exceeds even his former diligence.”
1849
A.D.
1774–1849
“With much confidence in you, either for Titus, &c. Some expound it of the confidence which this the third brother had in the Corinthians, but it seems rather to be understood of the confidence which St. Paul himself had in them, that they would shew great respect both to Titus, and to the other brethren whom he sent. He concludes, (ver. 24.) by exhorting them to these charitable contributions, which he calls the manifestation of their charity, in the sight of the Churches. Literally, in the face of the Churches, in your public meetings. (Witham) — Most commentators understand here Apollo, but without any certainty. (Bible de Vence)”
Source
1871
A.D.
1871
“This second brother, BIRKS supposes to be Trophimus: for a Macedonian is not meant (Co2 9:4) probably the same as was sent before with Titus (Co2 12:18); and therefore sent from Ephesus, and probably an Ephesian: all this is true of Trophimus. oftentimes . . . in many things--Join and translate as in the Greek, "many times in many things." upon the great confidence which I have in you--"through the great confidence WHICH HE HAS towards you" [ALFORD]. BENGEL better supports English Version, "We have sent . . . through the confidence WHICH WE FEEL in regard to your liberality."”
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.