This grace was especially manifested in various wondrous gifts and great signs of the divine dignity of Christian preaching. By the grace of God, according to Bishop Theophan, "the Apostle means not only elevation, purity, and detachment from selfish strivings, but also the manifestation of God's power through them."
Saint John Chrysostom remarks, "The Apostles were not without reason comforted and boasted in this. They were assured in themselves that they acted not by human power, but accomplished everything by the grace of God."
"They did this not only in Corinth, but in the whole inhabited world. For he says, 'we conducted ourselves in the world, and more abundantly toward you.' What does 'more abundantly toward you' mean? It means, by the grace of God we conducted ourselves."
"Among you we performed more wonders and signs, and we were especially careful to conduct ourselves so as not to deserve reproach from you." For it is known that in Corinth he renounced his rights regarding the support of preachers of the word of God.
It is noteworthy that when the Apostle speaks of this circumstance (1 Cor 9:15), he proceeds from the fact that no one could make his boasting void.
Here too he speaks of boasting, but more positively. He affirms not only that, in the awareness of his pure conscience, he can be an object of boasting for them.
He is also certain that the Corinthians partly recognize this. Above all, he hopes that it will be fully revealed on the day of the common judgment of the Lord.
Then, for the Apostles too, those who believed through them will be their best boasting. Thus, besides himself, the Apostle calls the Corinthians themselves as witnesses of his sincerity and constant faithfulness to himself, and points to Jesus Christ Himself.
"Thus," says Saint John Chrysostom in the Apostle's name, "although we are now afflicted, we have no small consolation, both from a good conscience and from the revelation expected then."
"Now our conscience alone knows that in everything we act by the grace of God, as you also know and will yet know. But then all men will know both our deeds and yours, and will see that we are glorified through one another."