In this day and time, many people seek for a way to protect themselves against things that war against the mind and body. Unfortunately, most people just look for worldly ways to protect themselves - like weapons, self defense, etc... But in all truth, the thing that is going to protect us more than anything else is God's word. The verse above tells us that the contents of God's word are sharper and more powerful than a two edged sword.
As Christians, we need to be studying God's word everyday and preparing ourselves to use it. Eph. 6:17 also tells us that it's our "sword," and we need to take it on as we put on the full armor of God.
Take the Word of God with you everyday.