"Now the man Moses was very humble" (Numbers 12:3) — for he heard the words [spoken against him] and said nothing to them, but kept silent; yet the Holy One, blessed be He, was concerned for the honor of Moses and demanded redress for the insult done to him. "Very humble" — humble in his mind, or is he not [called] humble except with regard to money? But it has already been said, "Carve out for yourself" (Exodus 34:1), [meaning] that the chips should be yours, and those stones that he carved were of sapphire, and from there Moses became rich [so it cannot be that he was "humble," i.e., poor, in money]. And if you should say he was humble in his body, that he was weak — but he came down upon Sihon and Og and slew them. Rather, [he was] humble in his mind, for he would hear his own disgrace and not answer back. "More than any person (adam)" — one might think [more humble than] the ministering angels, who are called "adam," as it is said, "and the likeness of their faces was the face of a man (adam)" (Ezekiel 1:10) — [that] he was humble. Therefore it is said "upon the face of the earth (adamah)," and not [more than] the ministering angels, concerning whom it is said, "And one called to another and said" (Isaiah 6:3). What did it mean to say [by this]? That each and every angel says to its fellow, "You speak first, for you are greater than I."
Why Moses Was Humbler Than Every Person and the Angels
Midrash Aggadah, Numbers 12:3
והאיש משה ענו מאד. ששמע הדברים ולא אמר להם דבר אלא שתק, אבל הקב"ה חשש לכבודו של משה ותבע עלבונו: ענו מאד. עניו בדעתו או אינו עניו אלא מממון, והלא כבר נאמר פסל לך (שמות לד א), שיהיה הפסולת שלך, ואותם אבנים שפסל של סמפרינון היה, ומשם נתעשר משה, ואם תאמר עניו בגופו שהיה חלש, והלא ירד על סיחון ועוג והרגם, אלא עניו בדעתו, שהיה שומע חרפתו ואינו משיב: מכל האדם. יכול ממלאכי השרת שנקראו אדם, שנאמר ודמות פניהם (מראה) [פני] אדם (יחקאל א י), היה עניו, לכך נאמר על פני האדמה, ולא ממלאכי השרת, שנאמר בהם וקרא זה אל זה ואמר (ישעי' ו ג), מה רצה לומר שכל מלאך ומלאך אומר לחבירו, אמור אתה ראשון, שאתה גדול ממני: