Matthew Poole and continuators on Numbers 12:10

10 And the cloud departed from off the tabernacle , and behold, Miriam became leprous , white as snow : and Aaron looked upon Miriam, and behold, she was leprous.

Not from the whole Tabernacle, for then they must have removed, but from that part of the Tabernacle, whither it was come, to that part which was directly over the Mercyseat, where it constantly abode.

She, and not Aaron, either because she was first or chief in the transgression; or because God would not have his worship either interrupted or dishonoured, which it must have been if Aaron had been leprous.

This kind of leprosie was the most virulent and incurable of all. See Exod. 4. 6. 2 King. 5. 27. It is true, when the leprosie began in a particular part, and thence spread it self over all the flesh by degrees, and at last made it all white, that was an evidence of the cure of the leprosie, Levit. 13. 12, 13. but it was otherwise when one was suddenly and extraordinarily smitten with this universal whiteness, which shewed the great corruption of the whole mass of blood, as it was here.

Marginal references: Deut. 24. 9.