Fred Sanders:
Such divine freedom is one of the things meant by grace. Notice how deeply imprinted this aspect of grace is, even into our language: When something is gratuitous (from gratia, grace) and given to us gratis (for free), the appropriate response is gratitude (responding to gratia) or gratefulness.
Sometimes when a person gets a surprise gift, he blurts out, “You didn’t have to do that!” Well, of course. That sentiment, too obvious to need saying, is a tiny meditation on the nature of the freedom that lies behind a true gift.
So is the redundancy of describing something as a “free gift,” as if there were any other kind of gift. Grace calls forth gratitude, and we answer with “thank you.”
This is also, by the way, why we say the word please when we ask for something. It is a shortened form of the expression, “If it pleases you,” which is a way of recognizing that the person you are asking a favor from is not your servant but a free person who isn’t required to do your bidding.
Good manners are good theology.
—The Deep Things of God, p. 65.