1 Thessalonians 2:3

For a work indeed it was of power, of mighty power, and such as no human diligence was equal to. For he brought three qualifications to the preaching of the word, a zeal fervent and venturous, a soul ready to undergo any possible hardship, and knowledge and wisdom combined. For his love of enterprise, his blamelessness of life, had availed nothing, had he not also received the power of the Spirit. And look at it as seen first in himself, or rather hear his own words. "That our ministration be not blamed." And again, "For our exhortation, is not of error, nor of uncleanness, nor in guile, nor a cloke of covetousness." Thus thou hast seen his blamelessness. And again, "For we take thought for things honorable, not only in the sight of the Lord, but also in the sight of men." … Without these things, the work had been impossible. It was not then by his miracles that men were made believers; no, it was not the miracles that did this, nor was it upon the ground of these that he claimed his high pretension, but upon those other grounds. For a man must be alike irreproachable in conduct, prudent and discreet in his dealings with others, regardless of danger, and apt to teach. It was by these qualifications that the greater part of his success was achieved.

"For our exhortation is not of error nor of uncleanness, nor in guile: but even as we have been approved of God to be entrusted with the Gospel, so we speak; not as pleasing men, but God which proveth our hearts." Do you see that, as I said, from their perseverance he makes a proof that the Preaching is divine? For, if it were not so, if it were a deceit, we should not have endured so many dangers, which allowed us not even to take breath. You were in tribulation, we were in tribulation. What then was it? Unless somewhat of things future had excited us, unless we had been persuaded that there is a good hope, we should not have been filled with the more alacrity by suffering. For who would have chosen for the sake of what we have here to endure so many sufferings, and to live a life of anxiety, and full of dangers? For whom would they persuade? For are not these things of themselves enough to trouble the disciples, when they see their teachers in dangers? But this was not your case. "For our exhortation," that is, our teaching, "is not of error." The matter, he says, is not guile nor deceit, that we should give it up. It is not for things abominable, as the tricks of jugglers and sorcerers. "And of uncleanness," says he, "nor in guile," nor for any insurrection. "But even as we have been approved of God to be entrusted with the Gospel, so we speak, not as pleasing men, but God." Do you see, that it is not vainglory? "But God," he says, "which proveth our hearts." We do nothing for the sake of pleasing men, he says. For on whose account should we do these things? Then having praised them, he says, Not as wishing to please men, nor seeking the honors that are from men, he adds, "But as we have been approved of God to be entrusted with the Gospel." Unless He had seen that we were free from every worldly consideration, He would not have chosen us. As therefore He approved us, such we remain, as having been "approved of God." Whence did he approve us, and entrust us with the Gospel? We appeared to God approved, so we remain. It is a proof of our virtue, that we are entrusted with the Gospel; if there had been anything bad in us, God would not have approved us. But the expression that He approved us, does not here imply search. But what we do upon proving, that he does without proving. That is, as he found us proof, and trusted us, so we speak; as it is reasonable that those should, who are approved and entrusted to be worthy of the Gospel, so we speak, "not as pleasing men," that is, not on your account do we do all these things.