The challenge to be courageous 
The 1828 edition of Noah Webster's dictionary says that "courage" comes from the French word for "heart." It means "to have heart." Courage is the quality that enables us to face danger and difficulty with firmness and without fear or depression. 

In defining courage, Webster cites Deuteronomy, chapter 31, where Moses is laying hands on Joshua and telling him to have courage. So I went to Webster for a definition of courage and he sent me back to Joshua. 

Joshua is one of the best biblical models of a courageous man. He was one of the twelve men who spied out the promised land; he and Caleb said it was possible to go into the promised land while the other ten said it was not. The majority prevailed. But Joshua stayed committed to God's purpose for forty years. 

When Moses died, Joshua succeeded him. The first message Joshua gets as a new leader is, "Moses is dead." This is more than a statement of fact; this is a statement of responsibility. 

The second message he gets is, "Arise, take these people across Jordan and take the land that's been promised to them." Joshua didn't have thirty days to mourn for Moses and then to go through his notes to be sure he knew what he was doing. It all came at once: "Moses is dead. You're the leader. Get them across the Jordan, and drive out the enemy." It seemed God gave Joshua an insurmountable mission. 

At this point God tells Joshua to be courageous. When God says something once we should take note. But he says it three times, and then adds, "don't tremble." That's a clue. 

See how Joshua responds. He doesn't look for a way to avoid confrontation. He doesn't only talk about taking the land. Rather he looks for a way to get over to the other side so he can deal with the enemy. Joshua also had the courage to inspire his people to face danger, to keep the rules, and to stay together when they want to divide. In fact, he banished discouragement among his people. 

We all know what happened. Through his courageous leadership, doing exactly what the Lord commanded regardless of the pain or risk, Joshua led his people into the promised land. 

We need to see the call to be courageous in the light of his mission to take the land. We cannot take the land and obtain God's promises without dealing with the issue of courage-that is, to be spiritually vigilant, alert, ready to spring into action, able to face danger (real danger, if we are talking about real promises) with firmness, and without fear of depression.