What I got from reading the Book of Joshua was that he was faithful to God. He trusted that The Lord was with him as long as he was with God. Joshua was not afraid being out numbered and out gunned in any battle The Lord gave to him. God guaranteed Joshua and the Israelites were protected as long as they followed every detailed instruction given to them.
One thing that stood out to me, not as odd, but as humbling was Joshua 5:13-15. Joshua was told that he was going to go into battle and concur Jericho. He had nothing to be afraid of because the power of God was with him. But when he confronts a man who is standing in front of him with a sword drawn, he asks “Are you and friend or foe?”, the man replies that he is the Commander of The Lord’s Army. Without hesitation Joshua drops down with his face in the ground, calls himself a servant, and then asks what he can do to please The Lord. That shows me that Joshua knows his place even after God confirms his power and authority on earth plus all the battles he will win.
I think that being humble and faithful, no matter how many victories we may have in life, are some characteristics that we can take away from The Book of Joshua.