One of the most important pieces of God's armor is the belt of truth. Everything flows out from truth. God's truth is absolutely necessary if we are to win the spiritual conflict with the devil who Jesus described as a liar and the father of lies.
Many Christians are unaware and therefore unprepared for spiritual warfare. But that need not be the case. God has provided every believer with all the information they need to prepare for the fight. But God has provided more than information, He has provided us with strength for the fight!