From Buck Parson in John Calvin: A Heart for Devotion, Doctrine and Doxology:
Humility is the supreme virtue according to Calvin, not only in attitude but in all of life. The Christian's humility should shine forth into the pompous darkness of this world. It is neither our eloquence nor our brilliance that directs men to God; rather, it is God who directs men to Himself through the seeming foolishness of preaching. Consequently, humility should conquer our minds and transform our hearts, arising from our study of God's majesty in His majestic Word.
For a great article on the difficulty (and need) of talking about humility see John Piper's "The Shy Virtue of Christmas."