God is faithful. By the term word he means doctrine, as is manifest from the reason that he adds, when he says, that the Son of God, who is preached by him, is not variable, etc. As to his being always consistent with himself in point of doctrine, and not differing from himself, [1] he intends that by this they shall form a judgment as to his integrity, and in this way he removes every unfavorable suspicion of fickleness or unfaithfulness. It does not, however, necessarily follow, that the man who is faithful in doctrine, is also observant of truth in all his words. But as Paul did not reckon it of much importance in what estimation he was held, provided only the majesty of his doctrine remained safe and sound, he, on that account, calls the attention of the Corinthians chiefly to that matter. He intimates, it is true, that he observed in his whole life the same course of fidelity, as the Corinthians had seen in his ministry. He seems, however, as if intentionally, in repelling the calumny, to transfer it from his person to his doctrine, because he was unwilling that his apostleship should be indirectly defamed, while he was not greatly concerned as to himself in other respects. But observe, with what zeal he applies himself to this. For he calls God to witness, how simple and pure his preaching was -- not ambiguous, not variable, not temporizing. In his oath, too, he connects the truth of God with the truth of his doctrine. "The truth of my preaching is as sure and stable as God is faithful and true." Nor is this to be wondered at, for the word of God, which Isaiah says endureth for ever, (Isaiah 40:8,) is no other than what prophets and apostles published to the world, as Peter explains it. (1-Peter 1:25.) Hence, too, his confidence [2] in denouncing a curse upon angels, if they dared to bring another gospel, one that was at variance with his. (Galatians 1:8.) Who would dare to make the angels of heaven subject to his doctrine, if he had not God as his authority and defense? With such an assurance of a good conscience does it become ministers [3] to be endowed, who mount the pulpit to speak the word in Christ's name -- so as to feel assured that their doctrine can no more be overthrown than God himself.

Footnotes

1 - "N'a point dit l'vn, puis l'autre;" -- "Does not say one thing and then another."

2 - "De là vient aussi que S. Paul est bien si hardi;" -- "Hence, too, it comes that St. Paul is so very bold."

3 - "Et annonciateurs de la parolle de Dieu;" -- "And heralds of the word of God."

But as God is true - Tyndale renders this in accordance more literally with the Greek, "God is faithful; for our preaching unto you was not yea and nay." The phrase seems to have the form of an oath, or to be a solemn appeal to God as a Witness, and to be equivalent to the expression "the Lord liveth," or "as the Lord liveth." The idea is," God is faithful and true. He never deceives; never promises that which he does not perform. So true is it that I am not fickle and changing in my purposes." This idea of the faithfulness of God is the argument which Paul urges why he felt himself bound to be faithful also. That faithful God he regarded as a witness, and to that God he could appeal on the occasion.
Our word - Margin, "preaching" (ὁ λόγος ho logos. This may refer either to his preaching, to his promises of visiting them, or his declarations to them in general on any subject. The particular subject under discussion was the promise which he had made to visit them. But he here seems to make his affirmation general, and to say universally of his promises, and his teaching, and of all his communications to them, whether orally or in writing, that they were not characterized by inconstancy and changeableness. It was not his character to be fickle, unsettled, and vacillating.

But as God is true - Setting the God of truth before my eyes, I could not act in this way: and as sure as he is true, so surely were my purposes sincere; and it was only my uncertainty about your state that induced me to postpone my visit. See 2-Corinthians 1:23.

(10) But [as] God [is] (r) true, our word toward you was not yea and nay.
(10) He calls God as witness and as judge of his constancy in preaching and teaching one self same Gospel.
(r) True, and of whose faithful witness it would be horribly wicked to doubt.

But as God is true,.... It seems that the false apostles had insinuated, that as the apostle had not kept his word in coming to them as he had promised, that he was not to be depended upon in his ministry; that he might as well contradict himself, and deceive others in the one, as well as in the other: wherefore he appeals to God in a very solemn manner, calls him to witness to the truth of his doctrine; for these words may be considered as the form of an oath; or he argues from, the truth and faithfulness of God, to the certainty and invariableness of the word preached, who is so true and faithful as that he will never suffer his word to be yea and nay: for when the apostle says, that
our word towards you was not yea and nay, he does not mean his word of promise to come to Corinth; but the word of his preaching, the doctrine of the Gospel, which was not uncertain, changeable, sometimes one thing, and sometimes another, and contradictory to itself. And by this the apostle would intimate, that since he was faithful and upright, uniform, consistent, and all of a piece in preaching the Gospel to them; so they ought to believe, that he was sincere in his resolutions and promises to come and see them, though as yet he had been hindered, and had not been able to perform them.

He adds this lest they might think his DOCTRINE was changeable like his purposes (the change in which he admitted in 2-Corinthians 1:17, while denying that it was due to "lightness," and at the same time implying that not to have changed, where there was good reason, would have been to imitate the fleshly-minded who at all costs obstinately hold to their purpose).
true--Greek, "faithful" (1-Corinthians 1:9).
our word--the doctrine we preach.
was not--The oldest manuscripts read "is not."
yea and nay--that is, inconsistent with itself.

Our word to you - The whole tenor of our doctrine. Hath not been yea and nay - Wavering and uncertain.