Who was Miriam?
Miriam was the sister of Aaron and Moses, oldest child of Amram and Jochebed. At least 12 or 13 at Moses' birth, for she is called (Exo. 2:8) "the maid," ha`almah(HSN-5959), implying one of marriageable age. Aaron being three years older than Moses was nine years younger than her.
She watched her infant brother in the ark on the Nile, and suggested to Pharaoh's daughter the mother as a nurse. In Micah 6:4 God mentions among benefits conferred on Israel, "I sent before thee Moses, Aaron, and Miriam," Miriam as the leader of and pattern to Israel's women.
She as "the prophetess, the sister of Aaron," with timbrel in hand, led the female choir who, with timbrels (round tambourines, an Egyptian word) and dances following her, sang the song of triumph at the Red Sea; they responsively took up the first strophe of the men's song (Exo. 15:1,20,21; so Judg. 11:34; 1 Sam. 18:6).
Her prophetic gift was perverted into a ground of jealousy of Moses, whose foreign Ethiopian wife, just espoused, to Miriam's disappointment had supplanted her from the influence which she had with Moses after Zipporah's death. "Miriam and Aaron spake against Moses because of the Ethiopian woman whom he had married (Num. 12) ... Hath the Lord indeed spoken only by Moses? Hath He not spoken also by us?"
But the phrase "sister of Aaron" (a phrase not likely to have been applied to Miriam by a later writer than Moses) marks her as ranking, not with Moses but with Aaron, and like him subordinate to Moses, the mediator of the Old Testament, and standing to Aaron "instead of God" (Exo. 4:16).
God's reply implies that, though receiving prophetical revelations, she did not receive them "mouth to mouth apparently" and immediately as Moses, who "beheld the similitude of the Lord," whereas she and others saw only in a "vision" or "dream." In wrath God withdrew the cloud from off the tabernacle, and behold the proud prophetess had the most humiliating of diseases, leprosy white as snow.
Miriam was the instigator, therefore on her alone fell the punishment. Aaron was influenced to evil by his sister, as before by the people (Exo. 32), with characteristic pliability. Leprosy was the penalty of sin against the theocracy, as in Uzziah's and Gehazi's case. Miriam became in a state of living death. Aaron interceded with Moses piteously for her: "let her not be as one dead, of whom the flesh is half consumed when he cometh out of his mother's womb." So Moses interceded with God: "heal her now, O God, I beseech Thee."
The Lord hearkened, but excluded her from the camp seven days; and such was her popularity, "the people journeyed not (from Hazeroth) until Miriam was brought in again." Her death was at Kadesh Barnea, the first month of the 40th year (Num. 20:1). Her sepulchre was shown in Eusebius' (Onom. in Jerome) time at Petra; but Josephus Ant. 4:4, section 6; 3:2, section 4, 6 section 1) places it on Mount Zin, and makes her wife of Hur and grandmother of the architect Bezaleel. Feminine jealousy and ambition were the drawbacks to her otherwise commanding character.
IBSE, "Isaac" (in the public domain) with minor edits.