Matthew Poole and continuators on Numbers 12:1

1 AND Miriam and Aaron spake against Moses, because of the Ethiopian woman , whom he had married, for he had married an Ethiopian woman.

Whom God permitted to murmur against their brother partly to exercise and discover the admirable meekness and patience for the instruction of after ages: and partly that by this shaking Moses his authority might take the deeper root, and the people might be deterred from all sedition and rebellion against him, by this example. Miriam seems to be first named, because she was the chief instigatour or first mover of the sedition, wherefore she also is more eminently punished.

Which was either 1. Zipporah, who is here called an Ethiopian, in the Hebrew a Cushite, because she was a Midianite: the word Cush being generally used in scripture, not for Ethiopia properly so called below Egypt, but for Arabia, as some late learned men have evidently proved from 2 King. 19. 9. 2 Chron. 21. 16. Ezek. 29. 10. and 30. 8, 9. Hab. 3. 7. and other places. If she be meant, as it is commonly conceived, I suppose they did not quarrel with him for marrying her, because that was done long since, but for indulging her too much, and being swayed by her and her relations, by whom they might think he was perswaded to make this innovation and to chuse seventy Rulers, as he had been formerly, Exod. 18. by which copartnership in government they thought their authority and reputation much diminished, especially when no notice was taken nor use made of them in the choice, but all was done by the direction of Moses and for his assistance in the government. And because they durst not accuse God, who was the chief agent in it, they charge Moses, his instrument, as the manner of men is. or 2. some other woman, though not named in Scripture, whom he married either whilest Zipporah lived, or rather because she was now dead, though that, as many other things; be not recorded. For, as the quarrel seems to be about his marrying a stranger, so it is probable it was a late and fresh occasion about which they contended, and not a thing done 40 years agoe. And it was lawful for him aswell as any other to marry an Ethiopian or Arabian woman, provided she were, as doubtless this woman was, a sincere proselyte, which were by the law of God admitted to the same priviledges with the Israelites, Exod. 12. 48. so there might be many reasons why Moses might chuse to marry such a person rather than an Israelite, or why God so ordered it by his providence, either because she was a person of eminent worth and vertue, or because God intended that the government should not be continued in the hands of Moses his children, and therefore would have some political blemish to be upon the family, as being strangers by one parent. And this they here urge as a blemish to Moses also.

Marginal references: Or, Cushite.; Exod. 2. 21.; Heb. taken.