(ג) וְהָאִ֥ישׁ מֹשֶׁ֖ה ענו [עָנָ֣יו] מְאֹ֑ד מִכֹּל֙ הָֽאָדָ֔ם אֲשֶׁ֖ר עַל־פְּנֵ֥י הָאֲדָמָֽה׃ (ס)
(3) Now Moses was a very humble man, more than any other man that was upon the face of the earth.
אמר רבא ואיתימא ר' יוחנן: גדול שנאמר במשה ואהרן יותר ממה שנאמר באברהם. דאילו באברהם כתיב, 'ואנכי עפר ואפר'. ואילו במשה ואהרן כתיב, 'ונחנו מה?'
Rava said (and some say it was Rav Yochanan), greater was that of what Moshe and Ahron said than that of what Avraham said. Avraham Said, "and I am dust and ash", whereas Moshe and Ahron said, "Who are we?"
Moshe was implying, "Who are we?
We are nothing, not even dust and ash"
שד''ל - שמות ד:י כבר התקומם רשב''ם נגד הסברה שמשה היה עילג ... והוא אומר שלא היה משה בקי בלשון מצרים. וגם זה באמת לא ייתכן, אחר שנתגדל במצרים ובבית המלך. והראב''ע קיים שהיה עילג ופירש "והוריתיך אשר תדבר" שישים בפיו מילות שאין בהם האותיות הכבדות עליו. אם כן יראה לנו הראב''ע מה הן האותיות שאינן נמצאות בפרשיות שאמר משה באזני כל העם, מלבד שזה גידוף כלפי מעלה שיבחר ה' לעשות שליח לתת תורה לעמו אדם שיצטרך לבחור המילות שיוכל לבטא אותן. והאמת, כי לא היה משה איש דברים, בעל כח הדיבור מרחיב פה ומאריך לשון בפני מי שיהיה ולא יחת מפני כל, זה מסכים למה שכתוב עליו "והאיש משה ענו מאד מכל האדם אשר על פני האדמה" (במדבר לב:ג). ... ויותר היה ענין קשה עליו אחר כמה שנים שהיה רועה את הצאן, ללכת לפני מלך גדול ולריב עמו.
Shadal - Shemot 4:10 - The Rashbam already argued against the position that Moshe stuttered...and he says that Moshe was not fluent in the language of Egypt. And this too is not possible after growing up in Egypt in the house of the king. And the Ibn Ezra proposed that he was a stutterer and interpreted that "I will instruct you what to say" means that God will give him words that do not have the letters that were difficult for him. If so, Ibn Ezra should show us which letter are not found in the sections where Moshe speaks to the Jewish people. Aside from this being an insult against the heavens, that God would choose an emissary to give the Torah to His people who needs to choose the words which he can pronounce. And the truth is that Moshe was not a man of words, a man with the power of speech, able to embelish and extend language in front of anyone and not be afraid. This understanding agrees with why it is written about Moshe: "And Moshe was very humble, more so than any man on earth" (Number 32:3). And Moshe conceded that this was difficult for him, to go in front of a great king and argue with him after spending years as a shepard,
דרשות הר''ן - הדרוש השלישי אבל עיקר הענין כי הנביא ראוי שיהיה שלם בכל השלמיות שהם ענין נכבד בעיני ההמון למעלת הכלל כי הוא שלוח אליהם, ולמען יהיו דבריו נשמעים וא''כ איך יתכן שתחסר למשה רבנו ע''ה מעלת שלימות הדבור? ...
והתשובה על זה: כי מהיות התורה וקבולה דבר היותר גדול שאפשר שיהיה במין האנושי, ראוי לעם שיקבלוהו שינתנו הוראות חזקות שהתורה ההיא אמתית, ושיוסר כל ספק מאותן ההוראות ומן הענין כלו בכללו שאינו בא כי אם בכח אלקי. ... ולזאת הסבה נשלם משה בכל שלמות נביא להאמין שענינו בכח אלקי והוסר ממנו בהשגחה גמורה הדבור הצח, למען לא יחשב שהיות כלל בני ישראל וגדוליהם נמשכים אחריו, יהיה להמשכם אחר צחות דבריו. כמו שידוע שיאמר על מי שהוא צח הדבור שימשיך לב ההמון אחריו, ושהשקר ממנו יחשב אמת. וזה הדבר כלו בהפך במי שהוא כבד פה, כי גם האמת ממנו לא יקובל כי אם בחוזק הגלותו. ולזאת הסבה היה כבד פה וכבד לשון בהשגחה גמורה, לא שיהיה דבר נופל במקרה. והוא מה שהשיבו ה' יתברך למשה על מה שהתמיה ואמר "לא איש דברים אנכי גם מתמול גם משלשום גם מאז דברך אל עבדך כי כבד פה וכבד לשון אנכי". ואמר "מי שם פה לאדם או מי ישום אלם או חרש או פקח הלא אנכי ה',". והיתה התשובה מספקת לשאלתו של משה.
Drashot HaRan - But the essential matter is that it is appropriate for a prophet to be whole in all ways, that these are matters of honor in the eyes of the multitude, to elevate the masses because he is sent to them, and so that his words should be heard. And if so, how is it possible that Moshe should lack perfect speech? ...and the answer is that the Torah and its acceptance is the greatest thing that can can happen to mankind, and the nation that accepts it should be given strong instruction that it is true and all doubt be removed, that the Torah came only through the power of God...and this is the reason that Moshe was complete in all areas, to believe that his teachings are through the power of God; through complete divine providence clear speech was taken from him, in order that no one would think that the people of Israel and their leaders follow him because of his clear words. As it is known that it is said about one who is a great speaker that he pulls the hearts of the masses after him, and lies from him sound as truths. And this is the opposite for one who is heavy mouthed, as even the truth is not accepted. And this is why Moshe was heavy mouthed - with divine design, and not by coincidence. And this is why God responds to Moshe when he says, "I am not a man of words..." with "Who gave man a mouth and who made a mute or a deaf or smart person?" And this answer was sufficient for Moshe's question.
Chabad.org
The Midrash says that when God was preparing to give the Torah, all the mountains stepped forward and declared why they thought the Torah should be given on them. "I am the highest mountain," said one. "No," said another, "I am the steepest mountain and therefore the Torah should be given on me."
One by one, they all stated their claims. In the end, God chose Mount Sinai - not because it was the tallest or the grandest, but because it was the most humble.
If G‑d wanted to emphasize humility, why did he give the Torah on a mountain? Shouldn't He have given it in a valley, or on the plains?
This teaches us about modesty and pride: A very strong personality can have an unassuming nature only by realizing that talents, genius, and skill come directly from G‑d. As the first paragraph in the Code of Jewish Law tells us, “Do not be embarrassed by those who mock you.” We, as Jews, do not have the luxury of being like a valley or a plain—of having our height and pride sapped from us. We should be like a mountain—and elevate ourselves with a strong identity.
Still, we must retain a sense of humility: we must be a mountain, but a low mountain.
"True humility is not thinking less of yourself, it is thinking of yourself less"
- C.S. Lewis
http://levechad.blogspot.com/2010/08/are-humility-and-self-esteem.html
Are Humility and Self-Esteem Contradictory?
The Chofetz Chaim was once traveling by train to a Jewish community to give a lecture. A man sat down next to him during the trip and started a conversation. When the Chofetz Chaim asked where he was heading, the man replied, "I'm going into town to hear the Chofetz Chaim speak. He's the greatest tzaddik (righteous person) in the Jewish world today." Embarrassed by what he was hearing, the Chofetz Chaim told the man, "People exaggerate about his greatness. I know him very well and he's not that great." The man became infuriated by what he was hearing and slapped the Chofetz Chaim in the face. That night, the man was horrified when he came to the lecture and realized that the person he hit was actually the Chofetz Chaim. As soon as the lecture was over, the man pleaded for forgiveness. The Chofetz Chaim smiled and said, "There's no need for forgiveness - you were defending me. In fact, you taught me a great lesson: my whole life I've been teaching people not to defame others; now I've learned that it's also wrong to defame yourself."
Humility isn't just about acknowledging that which you are not, it's also about recognizing that which you are. Thus, Moses is described as the most humble man who ever lived (Numbers 12:3). Yet, he could have also been referred to as the most courageous or the most compassionate human being of all time. Why does the Torah go out of its way to only mention this characteristic? Given the above definition of humility, it becomes clear as to why this was the case. Moses was quite aware of his weaknesses (including having a speech impediment), but at the same time also understood that his strengths put him in the position to lead the Jewish people. A lesser person would have either failed to acknowledge their weaknesses, or worse yet, would have downplayed the strengths they did possess in order to avoid greater responsibility.
Moshe repeatedly (and as a result, revealingly) says that his speech impediment prevents him from carrying out God’s mandate. God’s answer (Shemot 4:11)41 seems so obvious that one wonders why Moshe had not been embarrassed to even bring it up. It is manifestly clear that God is able to fix Moshe’s speech if it is necessary.42 We take it for granted that God knows what He is doing when He asks Moshe to be an emissary to Pharaoh. The obviousness of the answer and Moshe’s multiple repetition of the problem even after hearing God’s response (Shemot 6:12; Shemot 6:30).43 tell us to dig deeper. Indeed, the text mandates that we look below the surface.