The Torah tells us (Exodus 33:11 and elsewhere) that G-d spoke to Moshe "face to face" with a clarity not experienced by any other prophet. The Rambam tells us that Moses’ prophecy differed from that of other prophets in many other ways: among these, Moshe could receive prophecy while awake (as opposed to having to go into a trance-like state), prophecy was not a traumatic experience for him, and he did not require an angel to serve as an intermediary. Most notably, other prophets had to wait for G-d to contact them; only Moses was capable of initiating the dialogue with God.
The Torah also tells us (Numbers 12:3) that Moshe was the most humble person on the face of the Earth. How is that possible? Moshe committed the Torah to parchment word for word at G-d's dictation, so he knew what was in it; surely he was aware that his relationship with G-d was unique! How could he remain humble knowing that he was the only person ever to speak with G-d with this level on intimacy?
Of course Moshe knew who he was! He was well aware of his strengths. His modesty came from realizing that his gifts came from G-d. He recognized that G-d gives each of us certain abilities. The gift of strength or speed or wit - or even prophecy - comes from G-d. A talent or skill is not something we should allow to make us haughty or arrogant. It's a reason to thank G-d and to use those skills in His service. Unfortunately, too many people go to one extreme or the other: they are either overly pleased with themselves or they undervalue themselves. Egocentrism is a horrible trait but suffering from an unnecessarily poor self-esteem is equally bad!
Rav Simcha Bunim of Peshischa (1765–1827) had a suggestion for dealing with this delicate balancing act. He advised people to carry two notes in their pocket. On one was to be written "The entire world was created for my sake" (Sanhedrin 4:5), meant to encourage a person who could not see his own self-worth. On the other, "I am but dust and ashes" (Genesis 18:27), intended to deflate a person whose ego was over-inflated. By referring to the appropriate note as needed, a person can remember that man is the pinnacle of G-d's creation - but also that all men are temporal. We will not last forever and a lifetime's worth of our accomplishment's pale before even one of G-d's mighty deeds.
By clicking the link located above on this page, you can print out an attractive card based on the advice of Rav Simcha Bunim. Hopefully, with this constant reminder of man's greatness - but also of our limitations - we can aspire to the healthy self-esteem epitomized by Moshe.