The head of a household must punish and should not tolerate evil. But he must not be hateful and vengeful, lest in this way he corrupt the other person. A father does not punish his son in order to make him spiteful and ruin him in body and soul, but rather to ward off his vice; he wants to purify him and wipe away his faults. He hates, not the person, but the vice. This is a wrathful love which is kind and good toward the person; hence it cannot tolerate the nastiness in him. So, too, a woman cannot bear it when there is dirt on her child’s nose, but must wipe it away; she does not do this in order to hurt the child. Magistrates, teachers, and parents must chastise, but this chastisement is fatherly and kindly.
Solomon said, “Faithful are the wounds of a friend; profuse are the kisses of an enemy” [Prov. 27:6]. When an enemy speaks kindly to you, this is not affection, but rather the devil, who is out to destroy you in your sins. Ah, he says, you’re doing fine; go ahead! But a friend will be willing to hurt you. This is a rod, but it comes from the heart of a friend.”
Up to this point he has been speaking of being patient and bearing with our neighbor. He now goes on to speak of whoever receives a gift. [“As each has received a gift, employ it for one another, as good stewards of God’s varied grace” (I Pet. 4:10)]. If you speak, do so as one who speaks the Word of God. If you have an office, perform it as one who knows that it is of God.
(Luther’s Works, v. 51 , p.298).