Bible Verses about “christian simplicity”

“But let your 'Yes' be 'Yes' and your 'No' be 'No.' Whatever is more than these is of the evil one.”

“He has shown you, O man, what is good. What does Yahweh require of you, but to act justly, to love mercy, and to walk humbly with your God?”

“For our boasting is this: the testimony of our conscience, that in holiness and sincerity of God, not in fleshly wisdom but in the grace of God we behaved ourselves in the world, and more abundantly toward you.”