Parshat Shelah

In the story of the Sin of the Spies, It seems as though Calev is the only active defender of the land, as Yehoshua only joins him many verses later, in a much more passive way. What may explain this? By closely examining the story we can learn about the personalities of Calev and Yehoshua, where they each derive their strength to stand in the face of adversity, and about different forms of leadership.