14 For we stretch not ourselves beyond our measure, as though we reached not unto you: for we are come as far as to you also in preaching the gospel of Christ:
Paul did not go too far in what he was doing but stayed within the limits set for his task by God. He makes this explicit here so that the Corinthians will know that God has sent him to them and so they ought to obey his warnings. Otherwise they might appear to be resisting God, by whom Paul was sent.
"For we stretch not ourselves overmuch, as though we reached not unto you: for we came even as far as unto you in preaching the Gospel of Christ."
Not simply 'we came,' but, 'we announced, we preached, we persuaded, we succeeded.' For it is probable that they having merely come to the disciples of the Apostles, ascribed the whole to themselves, from their bare presence among them. 'But not so we: nor can any one say that we were not able to come as far as to you, and that we stretched our boasting as far as to you in words only; for we also preached the word to you.'
Probably, the false apostles and those who went somewhere without any preaching boast of their mere arrival and ascribe everything to themselves. So the apostle says: we do not overextend ourselves, as though we had not reached you, for we reached you not merely, but with the gospel of Christ, that is, we not only came, like those others, but also with the preaching of the Gospel.
That this is so, namely, that it reaches even to them, he proves when he says: For we are not overextending ourselves, as though we did not reach you. As if to say: of course we glory, but we do not stretch beyond ourselves in our grace or glory or power, as if we do not reach to you in our power and ministry: we were the first to come all the way to you with the gospel of Christ, i.e., in the preaching of Christ's Gospel: "For I became your father in Christ Jesus through the Gospel" (1 Cor. 4:15); "Are you not my workmanship in the Lord" (1 Cor. 9:1); "For he who worked through Peter for the mission to the circumcised worked through me also for the Gentiles" (Gal. 2:8).
[AD 384] Ambrosiaster on 2 Corinthians 10:14