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. Then you will be prosperous and successful.
If you're the leader of a million people and you're trying to keep the whole land 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 you pastures; today it means having a fat bank account and investments) and successful (success is still success).
Taken from Every Man, God's Man
BE A MAN.