The interpretation timeline
2 Corinthians 1:19 Douay-Rheims

For the Son of God, Jesus Christ who was preached among you by us, by me, and Sylvanus, and Timothy, was not, It is and It is not, but, It is, was in him.

A.D. 407 – 1871 7 witnesses

Patristic

before A.D. 750
407
A.D.
John Chrysostom Patristic
A.D. 347–407
“"For the Son of God," saith he, "Who was preached among you by us, even by me, and Silvanus, and Timothy, was not yea and nay." For on this account he brings before them the company of the teachers also, as thence too giving credibility to the testimony by those who taught, and not who heard it only. And yet they were disciples; however in his modesty he counts them as in the rank of teachers. But what is, "was not yea and nay?" I have never, he saith, unsaid what before I said in the Preaching. My discourse to you was not now this, now that. For this is not of faith, but of an erring mind. "But in Him was the yea." That is, just as I said, the word abideth unshaken and steadfast.”
Source
430
A.D.
Augustine of Hippo Patristic
A.D. 354–430
“And when we confess that we have lied, we speak the truth, for we are saying what we know, and we know that we have lied. That Word, however, which is God and more powerful than ourselves, cannot do this.… And of himself he does not speak, but of that Father is everything that he speaks, since the Father speaks it in a unique way. The great power of that Word is that he cannot lie, because in him there cannot be yes and no but yes, yes; no, no. For that is not even to be called a word if it is not true.”
Source

Scholastic

c. 1100 – 1500
1272
A.D.
Thomas Aquinas Catholic
1225–1274
“The Apostle, having won the good will of the Corinthians, next adds his excuse, and concerning this he does three things. First he sets forth his intention; second, under the form of a question, he sets out the accusation made against him by them, at the words when therefore this, etc.; third, he excuses himself, at the words but God is faithful. Concerning the first, it should be known that the Apostle, in a first letter (which we do not have) sent by him to the Corinthians, or through a messenger, had promised them that he would come to them first, before going into Macedonia, and through them would go into Macedonia, and again from there would return to Achaia, in which Corinth is, and from Achaia into Judea; but afterward, in the second letter, which we have as the first, he writes to them that he would go first into Macedonia, and afterward come to Corinth. Since therefore, according to this, it seems contrary to the first promise, the Apostle now excuses himself concerning this, setting forth first the promise itself as it was first made, and therefore he says and in this confidence, as if to say: you know my purity and my sincerity, and you are my witnesses, and my glory; therefore in this confidence, that is, trusting in this — since we hope to be glorified through one another — I wished to come to you first, that you might have a second grace, because a second visitation and confirmation in the faith is called a second grace with respect to the conversion which they first had through his ministry and preaching. And through you to pass into Macedonia, and again from Macedonia to come to you, and by you to be led on into Judea. This is the order of the first promise, but in the preceding letter the order is contrary, as has been said. Next he sets forth, under the form of a question, the accusation of this change, by which the Corinthians accused him, saying when therefore I had willed this, etc. Two things they imputed to him from this: fickleness, because he had changed his purpose — Ecclesiasticus 27:12: the fool is changed as the moon — and carnality, because it seemed to them that he had done this from some carnal and human affection. Hence he touches on these two, and first fickleness, and so he says did I use fickleness, if I did not do what I once willed? Far from it. Esther 16:9: nor should you think, if we command different things, that it comes from fickleness of mind. Psalm 34:18: in a weighty people, etc. Second he touches on carnality when he says or do the things which I think — whether to be done or to be left undone — do I think according to the flesh, that is, according to some carnal affection, so that with me there is yes and no, that is, affirmation and negation? Below, 10:2: they think that we walk according to the flesh. James 1:8: a man double-minded, etc. Having set out their accusation, he next excuses himself, saying but God is faithful, etc., and concerning this he does two things. First he intimates that he had not lied; second he shows the manner in which he was not lying, at the words but he who confirms, etc. That he had not lied, he excuses himself in two ways, namely from custom, and from cause. From custom indeed, because it ought not to be believed that someone easily lies who has never been found a liar; and according to this exposition, but God is faithful, etc., is taken in the force of an oath, as if to say: let God be my witness, that my word — namely of preaching — which was among you, is not in it yes and no, that is, there is no falsity in it. Deuteronomy 32:4: God faithful, and without any, etc. But if but God is faithful, etc., be taken for the truth of the divine promise, then the sense is: God is faithful, that is, he keeps his promises. Now he had promised to send to you preachers of truth, Jeremiah 3:15: I will give you shepherds according to heart, etc., and therefore, since I have been sent by him, our word which was, etc., as above. From cause he excuses himself, when he says for the Son of God. And this in two ways, namely the motive cause and the efficient cause, at the words but he who confirms, etc. Now the motive cause for not lying is this, that whoever takes up some office is naturally moved toward the things that are fitting to that office, and not toward the contrary. But it is evident that the apostolic office is to preach the truth; therefore he is not moved toward the contrary of truth, which is to lie. And concerning this he does three things. First he proves the truth of his own word through the word of Christ; second, the truth of Christ through the word of God, at the words for how many soever, etc.; third he concludes his intention, at the words therefore also through him, etc. He says therefore first: I say that our words ought to be reckoned true, and they are true, because we have preached Christ, in whom there was no falsity. And this is what he says, for the Son of God, Christ, who has been preached by us among you; by me, namely principally, and Silvanus, secondarily (this is Silas, of whom mention is made in Acts 18:5), and Timothy, of whom mention was made above. For these two were with the Apostle when he first converted them. In him, namely the Son of God, there was not yes and no, that is, falsity, nor did he do what was not fitting. But in him there was yes, that is, truth; for the true and being are convertible. John 14:6: I am the way, the truth, and the life. But because what he says might seem doubtful — that in Christ there was no falsity — he immediately proves this, adding for how many soever, etc. And he proves it in this way. It is evident that in that which is manifestative of the divine truth there cannot be falsity; the Son of God came to manifest the divine truth by fulfilling through himself the promises made by God; therefore in him there is no falsity. And this is what he says: in the Son of God there is not yes and no, but yes, because how many soever promises of God — namely, as have been made to men — in him, that is in Christ, are, that is, are verified and fulfilled in Christ. Romans 15:8: I say that Jesus Christ was a minister, etc. To confirm, etc. From these things, therefore, he concludes that since his words are true — because he preaches the Son of God, in whom is truth — therefore also through him, namely Christ, we say, amen to God, that is, true. Apocalypse 3:14: these things says the Amen, the faithful witness, etc. Isaiah 65:16: he who is blessed on the earth shall be blessed in God, amen, etc. And this truth we say to God, that is, to the honor of God, namely manifesting his truth and our glory, because our glory is your conversion. Or our glory, because our glory is to show forth and preach the word of God. Next, when he says but he who confirms, etc., the Apostle proves that he has not lied, through the efficient cause. For although a man, by free will, can use his tongue to speak either truth or falsehood, nevertheless God can confirm a man so firmly in truth that he speaks nothing but true things. If therefore God were to confirm someone in truth, it is manifest that he would not speak falsehood; but God confirms us in truth; therefore, etc. And therefore he says that it is God who confirms you with us in Christ, that is, in the true preaching of Christ, as if to say: if Christ were outside us, we could lie, but since he is with us, and we are in Christ, we do not lie. Psalm 74:4: I have confirmed its pillars, etc. We are therefore in Christ in two ways, namely through grace and through glory. Through grace indeed we are in him insofar as we have been anointed with the grace of the Holy Spirit, and have been made members of Christ, and joined to him. By which grace also Christ was anointed according as he is man. Psalm 44:8: God has anointed you, etc. And from the fullness of this anointing it overflowed onto all who are his, like the ointment on the head — namely on Christ — which descended, etc. And therefore he says that God has anointed us. He has anointed us, I say, as kings and priests. Apocalypse 5:10: you have made us to God, etc. 1 Peter 2:9: but you are a chosen race, etc. But the union which is through glory we do not have in reality, but in a certain hope, insofar as we have a firm hope of eternal life. And we have a twofold certitude of hope of attaining this union. One is through a sign, the other through a pledge. Through an evident sign, because of the faith. Hence he says he has sealed us with the sign of the faith of Christ. Likewise the sign of the cross. Ezekiel 9:4: mark thau, that is, the sign of the cross. Apocalypse 7:3: till we sign the servants of our God, etc. And this through the Holy Spirit. Romans 8:9: if anyone does not have the Spirit of Christ, etc. And therefore it is a special and certain sign of attaining eternal life to be configured to Christ. Canticle of Canticles 8:6: set me as a seal, etc. Or he has sealed us with the sign of life. But through the pledge, the greatest, because of the Holy Spirit, and therefore he says he has given the pledge of the Spirit in our hearts. Of which it is certain that no one can take it from us. But note, in a pledge two things are to be considered, namely that it produces the hope of having the thing, and that it is worth as much as the thing is worth, or more; and these two things are found in the Holy Spirit. For if we consider the substance of the Holy Spirit, thus the Holy Spirit is worth as much as eternal life, which is God himself, because he is worth as much as all three persons. But if the manner of having be considered, thus it produces hope, and not possession, of eternal life, because we do not yet perfectly have it in this life. And therefore we are not perfectly blessed, except when we shall have it perfectly in our homeland. Ephesians 1:13: you have been sealed with the Spirit. Next, when he says but I call God to witness, etc., he excuses himself concerning the fact that he did not come: and this through an oath, which is a greater thing. And concerning this he does three things. First he sets forth his excuse; second he answers a tacit question, at the words not that we dominate; third he explains what he says, at the words for by faith you stand. Now he excuses himself through a twofold oath. One of attestation, when he says but I call God to witness, the other of execration, when he says upon my soul, that is, against my soul. Romans 1:9: God is my witness, etc. As witness, I say, I call upon God, because I did not come again, that is, after the first time, or after I departed from you; and this I did, sparing you, namely because he knew them to be incorrigible. Hence, if he had gone then, either he would have punished them, and thus perhaps they would have withdrawn entirely from the faith; or he would not have punished them, and thus he would have given them occasion to sin the more. But because someone might say: why do you say sparing you? Are you not our lord? He therefore next removes this, saying not, I say, that we dominate over your faith, but are helpers, etc., as if to say: I do not say this as a lord, but as a fellow-helper. 1 Peter 5:3: not as lording it over the clergy, etc. A helper, I say, of your joy, or of your amendment. But why he says, of your faith, he next explains, saying for by faith you stand, that is, you stand in this grace of Christ through faith.”

Post-Reformation

c. 1650 – 1900
1771
A.D.
John Gill Reformed
1697–1771
“For the Son of God, Jesus Christ,.... The apostle having asserted that the Gospel preached by them was not yea and nay, variable and different, or what was affirmed at one time was denied at another, proceeds to point out the subject of the Gospel ministry, the Son of God, Jesus Christ; that Christ is "the Son of God": this article he began his ministry with, Act 9:20, and all the apostles affirmed the same thing; and which is of the greatest moment and importance, and ought to be abode by, insisted on, and frequently inculcated; as that he is the eternal Son of God, existed as such from everlasting, is of the same nature, and has the same perfections with his Father; and therefore is able to destroy the works of the devil, for which he was manifested in the flesh, and every way equal to the business of redemption, which he has finished; and having passed into the heavens under this character, is a powerful advocate with the Father; and which renders him a sure foundation for the church, and a proper object of faith: that the Son of God is Christ, anointed to bear and execute the office of a mediator in the several parts and branches of it; a prophet to teach his people, a priest to make atonement and intercession for them, and a King to govern and protect them: and that the Son, who is become the Lord's Christ, is Jesus, a Saviour; and that salvation is alone by him, to which he was appointed from eternity, and was sent in the fulness of time to effect it; and by his obedience, sufferings, and death, is become the author of it, and is the only able, willing, and suitable Saviour for poor sinners. This is the principal subject and strain of the Gospel ministry; and which makes it good news, and glad tidings to lost perishing sinners. The agreement between the faithful ministers of the Gospel is here plainly hinted, who was preached among you by us, even by me, and Silvanus and Timotheus. These ministers being mentioned by the apostle with himself, shows his humility in putting them on a level with himself; and his modesty and candour in not monopolizing the Gospel to himself, but allowing others to be preachers of it as well as he: and his design herein seems to be for the confirmation of the Gospel, and to show that he was not singular and alone, and could not be blamed by them, without blaming others; and chiefly to express the harmony and unanimity of Gospel preachers. The prophets of the Old Testament, and the apostles of the New, agreed in all the doctrines and truths of the Gospel; so did the apostles themselves; and so all faithful dispensers of the word have in all different times and places agreed, and still do agree; which serves greatly to corroborate the truth of the Gospel. The Gospel being faithfully preached by these persons, was not yea and nay; it had no contradiction in it; each part agreed together, was entirely harmonious, and consistent. Their doctrine was, that Christ is the Son of God, truly and properly God; that he took upon him the office of a Mediator, and executes it; that he is the only Saviour of sinners; that God has chosen a certain number of men in Christ before the foundation of the world, has made a covenant with them in Christ, and blessed them in him; that Christ has redeemed them by his blood; that these are regenerated by the Spirit and grace of Christ, are justified by his righteousness, and shall finally persevere, and be partakers of eternal life; which is all of a piece, and in it no yea and nay. Yea and nay doctrines are particular election, the possibility of the salvation of the non-elect, the salvability of all men, and universal redemption; justification by faith, and, as it were, by the works of the law; conversion, partly by grace, and partly by the will of man; preparatory works, offers, and days of grace; and final perseverance made a doubt of: but such is not the true ministry of Christ and his apostles, but in him was yea; the Gospel, as in Christ, and as it comes from him, and has been preached by his apostles, and faithful ministers, is all of a piece; its constant and invariable strain, and by which it may be known and distinguished, is, to display the free, rich, and sovereign grace of God, to magnify and exalt the person and offices of Christ, to debase the creature, and to engage persons to the performance of good works, on Gospel principles, and by Gospel motives, and for right ends. The apostle using those words, "yea and nay", conforms to the language of the Jews, his countrymen, who to magnify their doctors and Rabbins, and to raise their credit, say such things of them; ""yea, yea", are the words of the house or school of Shammai; , "yea, yea", are the words of the school of Hillell (b).'' And in another place (c); "the receiving and giving, or the dealings of a disciple of a wise man, are in truth and faithfulness. He says, , "concerning nay, nay, and concerning yea, yea".'' But what is here said better agrees with the principles and practices of the disciples and followers of Christ. (b) T. Bab. Moed Katon, fol. 20. 1. (c) Maimon. Hilch. Dayot, c. 5. sect. 13.”
Source
1832
A.D.
Adam Clarke Methodist
1762–1832
“For the Son of God, etc. - If I could have changed my purpose through carnal or secular interests then I must have had the same interest in view when I first preached the Gospel to you, with Silvanus and Timotheus. But did not the whole of our conduct prove that we neither had, nor could have such interest in view?”
1849
A.D.
1774–1849
“It is, was in him. There was no inconstancy in the doctrine of the apostles, sometimes, like modern sectaries, saying, It is, and at other times saying, It is not. But their doctrine was ever the same, one uniform yea, in Jesus Christ, one Amen, that is, one truth in him. (Challoner)”
1871
A.D.
1871
“Proof of the unchangeableness of the doctrine from the unchangeableness of the subject of it, namely, Jesus Christ. He is called "the Son of God" to show the impossibility of change in One who is co-equal with God himself (compare Sa1 15:29; Mal 3:6). by me . . . Silvanus and Timotheus--The Son of God, though preached by different preachers, was one and the same, unchangeable. Silvanus is contracted into Silas (Act 15:22; compare Pe1 5:12). in him was yea--Greek, "is made yea in Him"; that is, our preaching of the Son of God is confirmed as true in Him (that is, through Him; through the miracles wherewith He has confirmed our preaching) [GROTIUS]; or rather, by the witness of the Spirit which He has given (Co2 1:21-22) and of which miracles were only one, and that a subordinate manifestation.”
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.