Calvin's Commentaries, Vol. 4: Harmony of the Law, Part II, tr. by John King, [1847-50], at sacred-texts.com
30. But the soul that doeth ought presumptuously, whether he be born in the land, or a stranger, the same reproacheth the LORD; and that soul shall be cut off from among his people.
30. Anima quae fecerit in manu excelsa, tam civis quam peregrinus, ut Jehovam contumelia afficiat, ex-cidetur anima illa e medio populi sui.
31. Because he hath despised the word of the LORD, and hath broken his commandment, that soul shall utterly be cut off; his iniquity shall be upon him.
31. Quia sermonem Jehovae contempsit, et praeceptum ejus irritum fecit: excidendo excidetur anima illa: iniquitas ejus in ea.
30. But the soul that doeth ought. This verse is variously translated. For some read it thus 68 “The soul that doeth ought with a high hand, the same reproacheth the Lord, and, therefore, shall be cut off;” thus there would be two propositions. We have followed another opinion, reading it connectedly, “The soul, who shall have raised a high hand to the reproach of God, shall be cut off ” Literally, it is, “The soul, who shall have dealt with a high hand, whether born in the land, or a stranger, himself blaspheming God, and that soul shall be plucked up from the midst of his people.” But, since either version is probable, and makes no difference in substance, I have allowed myself freely to choose that which expressed the meaning more clearly. “To deal with a high hand” is nothing more than to attempt, or undertake proudly, what is not lawful: for our hands ought to be guided, and, as it were, restrained by God’s word, lest they should lift themselves up. But although men’s hands are used in various acts of audacity and wantonness, yet here there is especial mention of the profanation of God’s true and legitimate worship, when anything is invented inconsistent with its purity: for the punishment is not decreed against thefts, or murders, or other similar crimes, but against the perverse imaginations, which tend to the corruption of religion. The reason is afterwards added: “Because he hath despised the word of the Lord, and hath broken His commandment.” For it is no light offense to transgress the bounds which God hath placed. Now, it is certain that all self-invented services betray an impious contempt of God, as if men designedly despised Him, and spurned at His commands. Whence we infer, that nothing is more opposed to perfect and sincere religion than that temerity which induces men to follow whatever course they please. The clause, “his iniquity shall be upon him,” may be explained in two ways, either as a confirmation by Moses of the justice of this punishment, and of its merited infliction, or as an admonition, that the impiety should be corrected betimes, before it has advanced too far. There is no objection to either.