The interpretation timeline
2 Timothy 1:1 Douay-Rheims

Paul, an apostle of Jesus Christ, by the will of God, according to the promise of life, which is in Christ Jesus.

A.D. 407 – 1832 6 witnesses 7 excerpts

Patristic

before A.D. 750
407
A.D.
John Chrysostom Patristic
A.D. 347–407
“What is the reason of his writing this second Epistle to Timothy? He had said, "I hope to come unto thee shortly" (1 Tim. iii. 14), and as this had not taken place, instead of coming to him, he consoles him by a letter, when he was grieving perhaps for his absence, and oppressed by the cares of the government, which he had now taken in hand. For even great men, when they are placed at the helm, and are charged with the direction of the Church, feel the strangeness of their position, and are overwhelmed, as it were, by the waves of business. This was particularly the case when the Gospel was first preached, when the ground was everywhere unturned, and all was opposition and hostility. There were, besides, heresies commencing from the Jewish teachers, as he has shown in his former Epistle. Nor does he only comfort him by letters, he invites him to come to him: "Do thy diligence," he says, "to come shortly unto me," and, "when thou comest, bring with thee the books, but especially the parchments." (2 Tim. iv. 9 and 2 Tim. iv. 13.) And he seems to have written this Epistle when his end was approaching. For he says, "I am now ready to be offered up"; and again, "At my first answer no man stood with me." (2 Tim. iv. 6 and 2 Tim. iv.16) To set all this right, he both offers consolation from his own trials, and also says, "Paul, an apostle of Jesus Christ by the will of God, according to the promise of life which is in Christ Jesus." Thus at the very commencement he raises up his mind. Tell me not, he says, of the dangers here. These obtain for us eternal life, where there is no peril, where grief and mourning flee away. For He hath not made us Apostles only that we might encounter dangers, but that we might even suffer and die. And as it would not be a consolation to recount to him his own troubles, but rather an increase of his grief, he begins immediately with offering comfort, saying, "According to the promise of life which is in Jesus Christ." But if it is a "promise," seek it not here. For, "hope that is seen is not hope." (Rom. viii. 24.)”
Source
749
A.D.
John of Damascus Patristic
A.D. 676–749
“He wrote to him while he was hindered and bound in Rome. And therefore he urged him for a second letter. He begins by praising the student, that he is a slave to Christ who dwells above.”

Scholastic

c. 1100 – 1500
1273
A.D.
Thomas Aquinas Catholic
1225–1274
“By night and by day I was burned with heat and with frost, etc. Gen. XXXI, 40. These are the words of Jacob, showing and commending pastoral care, and the pastoral office; in which, concerning this office, three things are set down, namely diligence, patience, and solicitude. The first is that he ought to bear the care of the flock without interruption. Hence he says by night and by day. By night in praying, by day in teaching. Is. XXI, 8: Upon the watchtower of the Lord I stand continually by day, and upon my watch I stand through whole nights. Or by day, that is, in the time of prosperity; and by night, that is, in the time of adversity, in which the prelate ought to attend to the care of the flock. II Cor. VI, 7: through the arms of justice on the right hand and on the left. Prov. XVII, 17: He who is a friend loves at all times. The second is that patience is especially necessary for a prelate. For a prelate ought to endure all things for the sake of the salvation of the flock. Io. c. X, 11: The good shepherd gives his life for his sheep. Prov. XIX, 11: The learning of a man is known through patience. Hence he says with heat, that is, with the fervor of an impending persecution. Iac. I, 11: The sun arose with burning heat, and dried up the grass. Frost, that is, the fear of things to come. II Cor. VII, 5: without were fightings, within were fears. The third is that he presides in solicitude, as is said Rom. XII, 8. And this drives away the sleep of negligence. Hence it is added, Gen. XXXI, v. 41: and sleep fled from my eyes. Prov. VI, 3: run about, hasten, stir up your friend, do not give sleep to your eyes. Rightly, therefore, do these words fit the matter of this epistle. For in the first he instructs him concerning ecclesiastical ordination. But in this second he treats of such great pastoral solicitude, that he should even sustain martyrdom for the care of the flock, as is clear in the prologue.”
Source
“This epistle is divided into a greeting, and a narration. The second part begins at "I give thanks." Again, first the person greeting is set down; second, the person greeted; third, the goods wished for. The person greeting is described from the name "Paul," which signifies smallness, which befits him on account of humility of mind and tribulation, which make a man small — to such an extent that Christ is said to have been made small on account of his sufferings. Heb. 2:9: "him who was made a little lower than the Angels," etc. Again, from dignity, which he sets down first; second, the origin of the dignity; third, the fruit. The dignity is great, because he is "an apostle of Jesus Christ," that is, sent by Christ. Lk. 6:13: "he chose twelve from among them, whom he also named apostles." He obtained this dignity because he labored more than all, 1 Cor. 15:10, and Gal. 2:8: "he who worked in Peter unto the apostolate of the circumcision worked also in me among the Gentiles." The origin of the apostolate is the will of God, whence he says "through the will of God" — which some forestall, because they thrust themselves in; against whom it is said, Heb. 5:4: "no one takes the honor to himself, but he who is called by God, as Aaron was." Again, some are permitted it on account of the sins of the people. Job 34:30: "who makes a hypocrite man to reign, on account of the sins of the people." But this is "through the will of God," which he says, because not through his own will. The fruit, however, is not something earthly, but "according to the promise of life, which is," etc., that is, for obtaining the eternal life promised by Christ. This ought to be the end of prelates. 1 Cor. 9:25: "they indeed that they may receive a corruptible crown, but we an incorruptible one." Dan. 12:3: "they who instruct many unto justice, as stars unto perpetual eternities." The person greeted is Timothy, his son, converted by him, Acts 16:1. "Dearest," because of one mind with him. Phil. 2:20: "I have no one so of one mind," etc. The goods wished for are three, namely "grace," through which there is remission of sins; "mercy," through which we obtain the final good; "peace" — the Gloss: that is, tranquility of mind; this befits a prelate, who is appointed for this, that he may procure peace. In John, the Lord said: "peace be to you"; and he commanded those entering a house to offer peace, as is found in Matt. 10:12. And this "from God the Father," who is the giver of every good, Jas. 1:5. Again, "from Jesus Christ," who is mediator inasmuch as he is man, of God and men. 2 Pet. 1:4: "through whom he has given us the greatest and precious promises."”
Source

Post-Reformation

c. 1650 – 1900
1714
A.D.
Matthew Henry Reformed
1662–1714
“Here is, I. The inscription of the epistle Paul calls himself an apostle by the will of God, merely by the good pleasure of God, and by his grace, which he professes himself unworthy of. According to the promise of life which is in Christ Jesus, or according to the gospel. The gospel is the promise of life in Christ Jesus; life is the end, and Christ the way, Joh 14:6. The life is put into the promise, and both are sure in Christ Jesus the faithful witness; for all the promises of God in Christ Jesus are yea, and all amen, Co2 1:20. He calls Timothy his beloved son. Paul felt the warmest affection for him both because he had been an instrument of his conversion and because as a son with his father he had served with him in the gospel. Observe, 1. Paul was an apostle of Jesus Christ by the will of God; as he did not receive the gospel of man, nor was taught it, but had it by the revelation of Jesus Christ (Gal 1:12), so his commission to be an apostle was not by the will of man, but of God: in the former epistle he says it was by the commandment of God our Saviour, and here by the will of God. God called him to be an apostle. 2. We have the promise of life, blessed be God for it: In hope of eternal life, which God, who cannot lie, promised before the world began, Tit 1:2. It is a promise to discover the freeness and certainty of it. 3. This, as well as all other promises, is in and through Jesus Christ; they all take their rise from the mercy of God in Christ, and they are sure, so that we may safely depend on them. 4. The grace, mercy, and peace, which even Paul's dearly beloved son Timothy wanted, comes from God the Father and Christ Jesus our Lord; and therefore the one as well as the other is the giver of these blessings, and ought to be applied to for them. 5. The best want these blessings, and they are the best we can ask for our dearly-beloved friends, that they may have grace to help them in the time of need, and mercy to pardon what is amiss, and so may have peace with God the Father and Christ Jesus our Lord. II. Paul's thanksgiving to God for Timothy's faith and holiness: he thanks God that he remembered Timothy in his prayers. Observe, Whatever good we do, and whatever good office we perform for our friends, God must have the glory of it, and we must give him thanks. It is he who puts it into our hearts to remember such and such in our prayers. Paul was much in prayer, he prayed night and day; in all his prayers he was mindful of his friends, he particularly prayed for good ministers, he prayed for Timothy, and had remembrance of him in his prayers night and day; he did this without ceasing; prayer was his constant business, and he never forgot his friends in his prayers, as we often do. Paul served God from his forefathers with a pure conscience. It was a comfort to him that he was born in God's house, and was of the seed of those that served God; as likewise that he had served him with a pure conscience, according to the best of his light; he had kept a conscience void of offence, and made it his daily exercise to do so, Act 24:16. He greatly desired to see Timothy, out of the affection he had for him, that he might have some conversation with him, being mindful of his tears at their last parting. Timothy was sorry to part with Paul, he wept at parting, and therefore Paul desired to see him again, because he had perceived by that what a true affection he had for him. He thanks God that Timothy kept up the religion of his ancestors, Ti2 1:5. Observe, The entail of religion descended upon Timothy by the mother's side; he had a good mother, and a good grandmother: they believed, though his father did not, Act 16:1. It is a comfortable thing when children imitate the faith and holiness of their godly parents, and tread in their steps, Jo3 1:4. - Dwelt in thy grandmother and thy mother, and I am persuaded that in thee also. Paul had a very charitable opinion of his friends, was very willing to hope the best concerning them; indeed he had a great deal of reason to believe well of Timothy, for he had no man like-minded, Phi 2:20. Observe, 1. We are, according to St. Paul, to serve God with a pure conscience, so did his and our pious forefathers; this is to draw near with a true heart, in full assurance of faith, having our heart sprinkled from an evil conscience, Heb 10:22. 2. In our prayers we are to remember without ceasing our friends, especially the faithful ministers of Christ. Paul had remembrance of his dearly beloved son Timothy in his prayers night and day. 3. The faith that dwells in real believers is unfeigned; it is without hypocrisy, it is a faith that will stand the trial, and it dwells in them as a living principle. It was the matter of Paul's thanksgiving that Timothy inherited the faith of his mother Eunice and his grandmother Lois, and ought to be ours whenever we see the like; we should rejoice wherever we see the grace of God; so did Barnabas, Act 11:23, Act 11:24. I rejoiced greatly that I found of thy children walking in the truth, Jo2 1:4.”
Source
1771
A.D.
John Gill Reformed
1697–1771
“Paul an apostle of Jesus Christ,.... Not of men, nor by men, but by Jesus Christ, from whom he was sent; by whom he was qualified; in whose name he came, and ministered; and whom he preached. Of his name Paul, and of his office, as an apostle; see Gill on Rom 1:1 into which office he came by the will of God; not by the will of man, no, not of the best of men, of James, Cephas, or John, or any of the other apostles; nor by his own will, he did not thrust himself into this office, or take this honour upon himself; nor was it owing to any merits of his, which he always disclaims, but to the will and grace of God; it was by the secret determining will of God, that he was from all eternity separated unto the Gospel of Christ; and it was by the revealed will of God to the church, that he, with Barnabas, was set apart to the ministry of the word; see Rom 1:1. According to the promise of life which is in Christ Jesus; or "with respect unto it"; this points at the sum and substance, or subject matter, and end of his apostleship, for which this grace was given to him, which was to publish the free promise of life and salvation by Jesus Christ. By "life" here is meant, not this corporeal life, which, and a continuation of it, were promised in the covenant of works, on condition of man's obedience to it; but eternal life, the promise of which is a free promise made by God, of his own free sovereign will and pleasure, in the covenant of grace, from everlasting; and is an absolute and unconditional one, not at all depending upon the works of the law, or obedience to it; see Rom 14:16 and this promise is "in Christ", in whom all the promises are yea and arisen: for it was made before the world began, Tit 1:2 when the persons on whose account it was made were not in actual being; but Christ, their head and representative, then existed; and to him it was given, and into his hands was it put for them, where it is sure to all the seed; and not only the promise, but the life itself is in him, and which is here intended. Christ, as Mediator, asked it of his Father for all his people, and he gave it to him, where it is hid safe and secure. Christ is the Prince or author of life; he is the procuring cause of it; he was sent, and came, that his sheep might have it; he gave his flesh, his human nature for it; and by his sufferings and death removed all obstructions which sin had thrown in the way, and opened the way for their enjoyment of it; and he is the giver of it to as many as the Father has given him; nor is it to be had in any other way, or of any other; but of him; and it lies in the knowledge of him, communion with him, and conformity to him. Now it is the business, of Gospel ministers, not to direct persons to work for life, or to seek to obtain eternal life by their own works of righteousness, but to hold forth the word of life, or to show men the way of life and salvation by Christ alone.”
Source
1832
A.D.
Adam Clarke Methodist
1762–1832
“Paul an apostle - St. Paul at once shows his office, the authority on which he held it, and the end for which it was given him. He was an apostle - an extraordinary ambassador from heaven. He had his apostleship by the will of God - according to the counsel and design of God's infinite wisdom and goodness. And he was appointed that he might proclaim that eternal life which God had in view for mankind by the incarnation of his Son Jesus Christ, and which was the end of all the promises he had made to men, and the commandments he had delivered to all his prophets since the world began. The mention of this life was peculiarly proper in the apostle, who had now the sentence of death in himself, and who knew that he must shortly seal the truth with his blood. His life was hidden with Christ in God; and he knew that, as soon as he should be absent from the body, he should be present with the Lord. With these words he both comforted himself and his son Timothy.”
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.