A Commentary, Critical, Practical, and Explanatory on the Old and New Testaments, by Robert Jamieson, A.R. Fausset and David Brown  at sacred-texts.com
num 12:1MIRIAM'S AND AARON'S SEDITION. (Num 12:1-9)
an Ethiopian woman--Hebrew, "a Cushite woman"--Arabia was usually called in Scripture the land of Cush, its inhabitants being descendants of that son of Ham (see on Exo 2:15) and being accounted generally a vile and contemptible race (see on Amo 9:7). The occasion of this seditious outbreak on the part of Miriam and Aaron against Moses was the great change made in the government by the adoption of the seventy rulers [Num 11:16]. Their irritating disparagement of his wife (who, in all probability, was Zipporah [Exo 2:21], and not a second wife he had recently married) arose from jealousy of the relatives, through whose influence the innovation had been first made (Exo 18:13-26), while they were overlooked or neglected. Miriam is mentioned before Aaron as being the chief instigator and leader of the sedition.
num 12:2Hath the Lord indeed spoken only by Moses? hath he not also spoken by us?--The prophetical name and character was bestowed upon Aaron (Exo 4:15-16) and Miriam (Exo 15:20); and, therefore, they considered the conduct of Moses, in exercising an exclusive authority in this matter, as an encroachment on their rights (Mic 6:4).
num 12:3the man Moses was very meek-- (Exo 14:13; Exo 32:12-13; Num 14:13; Num 21:7; Deu 9:18). This observation might have been made to account for Moses taking no notice of their angry reproaches and for God's interposing so speedily for the vindication of His servant's cause. The circumstance of Moses recording an eulogium on a distinguishing excellence of his own character is not without a parallel among the sacred writers, when forced to it by the insolence and contempt of opponents (Co2 11:5; Co2 12:11-12). But it is not improbable that, as this verse appears to be a parenthesis, it may have been inserted as a gloss by Ezra or some later prophet. Others, instead of "very meek," suggest "very afflicted," as the proper rendering.
num 12:4the Lord spake suddenly unto Moses, and unto Aaron, and unto Miriam--The divine interposition was made thus openly and immediately, in order to suppress the sedition and prevent its spreading among the people.
num 12:5the Lord came down in the pillar of the cloud, and stood the door of the tabernacle--without gaining admission, as was the usual privilege of Aaron, though it was denied to all other men and women. This public exclusion was designed to be a token of the divine displeasure.
num 12:6Hear now my words--A difference of degree is here distinctly expressed in the gifts and authority even of divinely commissioned prophets. Moses, having been set over all God's house, (that is, His church and people), was consequently invested with supremacy over Miriam and Aaron also and privileged beyond all others by direct and clear manifestations of the presence and will of God.
num 12:8with him will I speak mouth to mouth--immediately, not by an interpreter, nor by visionary symbols presented to his fancy.
apparently--plainly and surely.
not in dark speeches--parables or similitudes.
the similitude of the Lord shall he behold--not the face or essence of God, who is invisible (Exo 33:20; Col 1:15; Joh 1:18); but some unmistakable evidence of His glorious presence (Exo 33:2; Exo 34:5). The latter clause should have been conjoined with the preceding one, thus: "not in dark speeches, and in a figure shall he behold the Lord." The slight change in the punctuation removes all appearance of contradiction to Deu 4:15.
num 12:10MIRIAM'S LEPROSY. (Num 12:10-16)
the cloud departed from the tabernacle--that is, from the door to resume its permanent position over the mercy seat.
Miriam became leprous--This malady in its most malignant form (Exo 4:6; Kg2 5:27) as its color, combined with its sudden appearance, proved, was inflicted as a divine judgment; and she was made the victim, either because of her extreme violence or because the leprosy on Aaron would have interrupted or dishonored the holy service.
num 12:11On the humble and penitential submission of Aaron, Moses interceded for both the offenders, especially for Miriam, who was restored; not, however, till she had been made, by her exclusion, a public example [Num 12:14-15].
num 12:14her father had but spit in her face, should she not be ashamed seven days?--The Jews, in common with all people in the East, seem to have had an intense abhorrence of spitting, and for a parent to express his displeasure by doing so on the person of one of his children, or even on the ground in his presence, separated that child as unclean from society for seven days.
num 12:15the people journeyed not till Miriam was brought in again--Either not to crush her by a sentence of overwhelming severity or not to expose her, being a prophetess, to popular contempt.
num 12:16pitched in the wilderness of Paran--The station of encampments seems to have been Rithma (Num 33:19).