Moses was the elder of Joshua, and an established leader of the people. Joshua was a youth and a leader of the army of God. Moses told Joshua that he was to choose some men to go out and fight. Joshua did as Moses had asked. There were no conflicts of interest, for both had no self-interest. Their interest was for the people of God.
Joshua could have told Moses, "Why don't you go into battle and risk your life instead of asking me to risk mine?" Joshua could also have responded to Moses with a whole lot of excuses. Imagine if he had said, "No, I have a better suggestion. I will take the rod of God, and you, Aaron and Hur will go down to the battle." If the attention of Joshua and Moses were focused on each other and themselves, truly the enemy would have approached and destroyed the whole nation of Israel.
In Joshua's mind there was no thought that Moses had the easier job and that his was more difficult. He held no resentment towards Moses. Everything was conducted in an orderly manner. Both of them were focused on the one thing: the safety of the people of God. Each did their part and accomplished victory.
If Joshua had fought casually and not led the people into battle with a courageous heart then victory would not have been theirs. If Moses had not focused keeping the rod of God raised then Joshua could have lost his life and the lives of other men. Both had the mind of God and exerted their human effort towards the same goal. And God surely gave them the victory. The victory was the Lord's. From this incident we can see how important it is for of two generations must be fused together based on truth to bring great glory to God.