זכור את אשר עשה יקוק אלקיך למרים. אִם בָּאתָ לְהִזָּהֵר שֶׁלֹּא תִלְקֶה בְּצָרַעַת אַל תְּסַפֵּר לָשׁוֹן הָרָע, זְכֹר הֶעָשׂוּי לְמִרְיָם שֶׁדִּבְּרָה בְאָחִיהָ וְלָקְתָה בִנְגָעִים (עי' ספרי):
In view of all these considerations it is easy to understand why the Torah looks askance at any assembly of fools, loiterers, people engaged in pointless and unproductive conversation. Solomon makes this plain in Kohelet 8,2 when he said that foolishness is the result of too much talk. Such talk will easily degenerate into sinful talk, character-assassination of one’s peers and the like. Once one has begun to speak disparagingly about one’s peers it is only a short step away from criticizing Torah scholars as we know from Psalms 31,19: “let lying lips be stilled that speak haughtily against the righteous with arrogance and contempt.” Once one is not afraid to speak about the righteous, one will start putting down G’d’s prophets, and in the end one will speak out against G’d Himself. We have examples of all this in Chronicles II 36,15: “but they mocked the messengers of G’d and disdained His words and taunted His prophets until the wrath of G’d against His people grew beyond remedy.” Compare also Psalms 73,9: “they set their mouths against heaven, and their tongues range over the earth.” Who was the cause that they set their mouths against heaven? Their tongues which had begun by speaking about earthly matters.
(15) The king of Egypt spoke to the Hebrew midwives, one of whom was named Shiphrah and the other Puah,
Miram and Aharon spoke against Moses because of the Cushite woman he had married: “He married a Cushite woman!” They said, “Has the LORD spoken only through Moses? Has He not spoken through us as well?” The LORD heard it. Now Moses was a very humble man, more so than any other man on earth. Suddenly the LORD called to Moses, Aaron, and Miriam, “Come out, you three, to the Tent of Meeting.” So the three of them went out. The LORD came down in a pillar of cloud, stopped at the entrance of the Tent, and called out, “Aaron and Miriam!” The two of them came forward; and He said, “Hear these My words: When a prophet of the LORD arises among you, I make Myself known to him in a vision, I speak with him in a dream. Not so with My servant Moses; he is trusted throughout My household. With him I speak mouth to mouth, plainly and not in riddles, and he beholds the likeness of the LORD. How then did you not shrink from speaking against My servant Moses!” Still incensed with them, the LORD departed. As the cloud withdrew from the Tent, there was Miriam stricken with snow-white scales! When Aaron turned toward Miriam, he saw that she was stricken with scales.
Rabbi Joseph B. Soloveitchik, Vision and Leadership p.178
Miriam and Aaron did not grasp the incommensurability of Moses' prophecy with that of other prophets. Moses spent forty days and nights on Sinai, where he did not eat or drink. He belonged to a different existential order of creation, one where the logos and ethos of other prophets do not apply. Their sin was in not understanding that he was the prophet sui generis, singular, unparalleled, and unmatched: "Not so My servant Moses" (Num. 12:7).
(ז) אֲנִי מַאֲמִין בֶּאֱמוּנָה שְׁלֵמָה שֶׁנְּ֒בוּאַת משֶׁה רַבֵּֽנוּ עָלָיו הַשָּׁלוֹם הָיְ֒תָה אֲמִתִּית וְשֶׁהוּא הָיָה אָב לַנְּ֒בִיאִים לַקּוֹדְ֒מִים לְפָנָיו וְלַבָּאִים אַחֲרָיו:
(7) 7. I believe with complete faith that the prophecy of our teacher, Moses, may he rest in peace, was true, and that he was the father of all prophets, —of those who preceded him, and of those who followed him.