John Calvin Commentary Psalms 101:5

"Whoso privily slandereth his neighbor, him will I destroy: Him that hath a high look and a proud heart will I not suffer." — Psalms 101:5 (ASV)

Whoever slanders his neighbor in secret, him will I destroy. In this verse, he speaks more distinctly of the duty of a king who is armed with the sword for the purpose of restraining evildoers. Slander, pride, and vices of every description are justly offensive to all good people; but not all people have the power or right to cut off the proud or slanderers, because they are not invested with public authority and consequently have their hands bound.

It is important to note this distinction, so that the children of God may keep themselves within the bounds of moderation, and that no one may go beyond the sphere of his own calling. It is certain that as long as David lived merely as a private citizen, he never dared to attempt any such thing.

But after being placed on the royal throne, he received a sword from the hand of God, which he used in punishing evil deeds. He specifies certain kinds of wickedness so that, by mentioning one type (using the figure of speech synecdoche), he might indicate his determination to punish all sorts of wickedness.

To slander another's reputation secretly and by stealth is an exceedingly destructive plague. It is as if a person killed a fellow human being from a place of ambush; or rather, a slanderer, like one who administers poison to an unsuspecting victim, destroys people unawares. It is a sign of a perverse and treacherous disposition to damage the good name of another when that person has no opportunity to defend himself. This vice, which is too prevalent everywhere, yet ought not to be tolerated among people, David undertakes to punish.

He next characterizes the proud using two expressions. He describes them as those whose eyes are lofty—not because all who are proud look with a lofty countenance, but because they commonly betray the arrogance of their proud hearts by the loftiness of their countenance. He further describes them as wide of heart, because those who aspire to great things must necessarily be puffed up and swollen.

They are never satisfied unless they swallow up the whole world. From this we learn that good order cannot exist unless princes are diligently on watch to repress pride, which necessarily brings with it and engenders outrage and cruelty, contemptuous language, plunder, and all kinds of ill-treatment. Thus it would happen that the simple and the peaceable would be at the mercy of the more powerful, if the authority of princes did not intervene to curb the audacity of the latter.

Since it is the will of God that good and faithful kings should hold pride in detestation, this vice is unquestionably the object of his own hatred. What he therefore requires from his children is gentleness and meekness, for he is the declared enemy of all who strive to elevate themselves above their condition.