After the death of Moses, Joshua faced the most challenging task of his life–conquering a new land. The secret to his success, however, was not in the size of his armies, the speed of his chariots, or the will of his people. Joshua’s secret was to obey God’s command:
Do not let this Book of the Law depart from your mouth; meditate on it day and night, so that you may be careful to do everything written in it. They you will be prosperous and successful. (JOSHUA 1:8, emphasis added)
If you’re the leader of a million people and you’re trying to keep the whole deal together in addition to overtaking foreign lands occupied by people who don’t like you, what would you say is the X-factor for success? God said it was to think deeply and continuously on His Word so that you will do what He says first. Then you will be prosperous (in those days, that meant having a lot of sheep in your pastures; today it means having a fat bank account and investments) and successful (success is still success).