He that deviseth to do evil shall be called a mischievous person To do evil is natural to men, all are prone to it; being conceived and born in sin, and, from the womb, more or less commit it: but for a man to sit down and contrive evil, as some men are inventors of evil things; contrive new sins, or at least new methods of sinning, such as new oaths, new games, new ways of tricking and deceiving men; and are always studying and devising ways and means of committing sin, and doing that which is evil in the sight of God and men. Such a man, with great propriety, may be called, and will be called by those that know him, a mischievous man, a very pernicious one, and to be shunned and avoided as such; men will reckon him and call him a "master" or "author (d) of evil devices", as it may be rendered; a name agreeable to his character.
(d) "patronum malarum cogitationum", Montanus; "dominum", Mercerus, Gejerus; "auctorem", Michaelis.

So called even if he fails to do evil.

From wisdom, which is a moral good, the following proverb passes over to a kind of σοφία δαιμονιώδης:
He that meditateth to do evil,
We call such an one an intriguer.
A verbal explanation and definition like Proverbs 21:24 (cf. p. 29), formed like Proverbs 16:21 from נבון. Instead of בּעל־מזמּות [lord of mischief] in Proverbs 12:2, the expression is 'אישׁ מ (cf. at Proverbs 22:24). Regarding מזמות in its usual sense, vid., Proverbs 5:2. Such definitions have of course no lexicographical, but only a moral aim. That which is here given is designed to warn one against gaining for himself this ambiguous title of a refined (cunning, versutus) man; one is so named whose schemes and endeavours are directed to the doing of evil. One may also inversely find the turning-point of the warning in 8b: "he who projects deceitful plans against the welfare of others, finds his punishment in this, that he falls under public condemnation as a worthless intriguer" (Elster). But מזמות is a ῥῆμα μέσον, vid., Proverbs 5:2; the title is thus equivocal, and the turning-point lies in the bringing out of his kernel: מחשּׁב להרע = meditating to do evil.

Shall be called - Though he cover his wicked devices with fair pretences, he shall be branded with that infamy which is due to him.