For our boast is this, the testimony of our conscience, that we behaved in the world with simplicity and godly sincerity, not by earthly wisdom but by the grace of God, and supremely so toward you.
12. For our glorying is this. He assigns a reason why his preservation should be a subject of interest to all — that he had conducted himself “We have had our conversation (ἀνεστράφημεν.) The verb ἀναστρέφω, is compounded of ἀνὰ, again, and στρέφω, to turn — a continual coming back again to the point from which he set out — a circulation — beginning, continuing...
The apostle in these verses attests their integrity by the sincerity of their conversation. This he does not in a way of boasting and vain-glory, but as one good reason for desiring the help of prayer, as well as for the more comfortably trusting in God (Heb 13:18), and for the necessary vindication of himself from the aspersions of some persons at Corinth, who reproached...
Commenting on 2 Corinthians 1:12-14
For our rejoicing is this, the testimony of our conscience,.... This rejoicing or glorying of the apostle's in the testimony of their consciences, to the goodness of their hearts, actions, conduct, and behaviour, was not before God, and in his sight, but before men, who were ready to accuse their good conversation in Christ: nor are these words to be considered as they generally are...