King James Version
For our rejoicing is this, the testimony of our conscience, that in simplicity and godly sincerity, not with fleshly wisdom, but by the grace of God, we have had our conversation in the world, and more abundantly to you-ward.English Standard Version
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.New International Version
Now this is our boast: Our conscience testifies that we have conducted ourselves in the world, and especially in our relations with you, in the holiness and sincerity that are from God. We have done so not according to worldly wisdom but according to God's grace.