Proverbs 27:6

The proverb sets two things side by side that we habitually rank the other way around: the friend who wounds us, and the flatterer whose kisses come easy and often. On the surface the kisses look like the better deal — warm, affirming, pleasant to receive. But flattery asks nothing true of us and costs the flatterer nothing; it is a way of managing us, keeping us comfortable and keeping us at a distance. A friend's honest wound is the opposite. It costs them something to say the hard thing — the risk of our anger, the possible loss of the friendship — and they say it anyway, because they would rather we be well than merely be pleased with them. That is what makes the wound faithful. We are wired to prefer the soft lie; almost no one enjoys being told the truth about themselves. But the sages understood a loneliness that flattery cannot cure: to be handled gently and admiringly by people who do not actually know you is a thinner, colder thing than to be told the truth by someone who does. The friend who can wound you is usually the friend who has bothered to see you clearly — and to be seen clearly and loved anyway is worth more than any amount of comfortable, undemanding approval. Wisdom teaches us to receive the faithful wound without flinching away from the one who gave it, and to be a little suspicious of any relationship in which no one ever risks telling us something we would rather not hear.

Keller draws out why the wound is the faithful thing. The flatterer's kiss offers love without knowledge; the friend's wound is love that actually knows us — and being known and still loved, Proverbs and Keller agree, is worth more than any amount of comfortable distance.