The Israelites decided to not fight for the land that God had given them. They decided it wasn’t worth the effort. Before a battle would even begin they determined that they would fail. This sounds so strange because God had promised them the victory. 
How often do we surrender to fear, doubt, tribulation or failure because we rely on our thoughts and don’t put any stock into what God has promised us?
God has peace, confidence and success for us. We have to be willing to battle for it by putting our flesh aside, rising up in the strength of Christ and believing his promises.
Scripture taken from: Numbers 13:26-31