From our archived blog:
In part one we established two major things. 1) Moses, the greatest leader that the Israelites have ever known, described as the servant of the LORD, has died. 2) God is now speaking to Joshua, Moses' assistant. If I had been in Joshua's place, I might of called my self Moses' lowly assistant. Any rate this is the first blow that Joshua gets. The leader whom had lead the Israelites out of the most powerful nation at the time, whom had preformed signs and wonders for God in the sight of powerful men, and the man whom and lead that stubborn people for over 40 years, was now dead. This would have created a vacuum of power. You can only gather from the inference that the people saw Joshua as "Moses' assistant" and not the servant of the LORD, the leader of Israel.
However, the verse has not even stopped here! Verse 2 after "Moses my servant is dead." goes like this, "Now therefore, arise, go over this Jordan, you, and all this people, into the land that I am giving to them, to the people of Israel." Ok so Moses the, servant of the LORD, this man described as none of the other prophets are like him, has died. We got that part, but now God says that Joshua, Moses' assistant, get up, go over the Jordan. That river that marks the boundary between them and that land God had promised. The land that 12 spies (including Joshua) had gone into; describing the men as giants them only being grasshoppers in their sight! If that wasn't bad enough God hasn't stopped speaking, "you and all this people..." 
You, Joshua, Moses' assistant, take this people whom mumored in the desert for 40 years, whom worshiped a golden calf, and even challenged Moses' authority from time to time. All while Moses was still alive, and he's dead now! God then says, "into the land that I am giving to them, to the people of Israel." Reminding them of the promise that He has made to not only Moses, but all the other patriarchs as well.
God then begins to promise, "Every place that the sole of your foot will tread upon I have given to you, just as I promised Moses." He then follows this up with the boundaries. What a promise! A promise that would not come to fruition if Joshua would have say turned the other way because the problem was just too big. Or it was just too fearful. After all, he, Moses' assistant, was only a grasshopper in the eyes to the men whom he was to conquer. Do you think Joshua was afraid? Do you think he wanted anything other then to have been Moses' assistant? I do.
Part 1
All Scripture is from the English Standard Version. In context: Joshua 1.