John Calvin Commentary Numbers 12:9

"And the anger of Jehovah was kindled against them; and he departed." — Numbers 12:9 (ASV)

And the anger of the Lord was kindled against them. The rebuke is followed by punishment. God’s departure was a sign of immediate condemnation, because there was no need for any further questioning about some obscure matter. After God, then, had convicted them of their sin, and had inveighed with a severe and stern rebuke against the ingratitude of Miriam and Aaron, He first pronounced their sentence, and then suddenly withdrew. What follows, that the cloud departed, is added in explanation. For God, who fills all things, never moves from His place; but His name is applied metaphorically to the cloud, which was the symbol of His absence or presence.

The nature of the punishment inflicted upon Miriam was very appropriate to the offence. The foolish woman, puffed up with pride, had coveted more than was lawful; and her ignominy was the just reward of her arrogance, according to the declaration of Christ, Every one that exalteth himself shall be abased (Luke 18:14).

Let us understand, then, that to the extent that the proud are led away by their ambition to long for unlawful honors, they bring upon themselves nothing but disgrace. Although they may gloriously triumph for a season, still, their glory must at last be turned into disgrace. For since all who exalt themselves wage war with God, He must encounter them with the awful power of His hand, in order to restrain their madness. Now, whoever are moved by envy to enter into contention with His servants, endeavor, as far as they are able, to overthrow His glory by obscuring the gifts of the Spirit. No wonder, then, that God should avenge the insult offered to Himself, and should repay them with the infamy they deserve, as it is written:

Them that honor me I will honor, and they that despise me shall be lightly esteemed (1 Samuel 2:30).

Miriam desired to be equal with her brother, whom God had exalted above all others. What she attains is that she would not occupy even the remotest corner among the people, but be cut off from companionship with mankind. A similar instance occurred in the case of King Uzziah, who, not content with the royal dignity, when he had unlawfully attempted to make an incense-offering, was also struck with leprosy, so that he was no longer permitted to continue in association even with the common people (2 Chronicles 26:16–21).

Here, however, the question arises: why, when Aaron participated in the guilt, was he exempted from the punishment? If no reason existed, we should still adore the judgment of God, for it is not our business to complain when He has mercy on whom He will have mercy. Nevertheless, it appears probable that God’s wrath was kindled more intensely against Miriam because she had applied the torch to the ungodly contention and had inflamed her brother’s mind, as we see at the beginning of the chapter. It was just, then, that the blame should rest on her, since she had been the origin of the evil.

I imagine, however, that in sparing Aaron, He had regard for the priesthood, since, in his person, it would have been subjected almost to eternal disgrace. Since, therefore, Aaron was an image of God’s only-begotten Son and our only Mediator, and this great dignity had recently begun in him, it was extremely important that he should be exempted from such infamy, lest any diminution of the reverence due to religion should arise.