The sword is an offensive weapon. In biblical times a Roman sword had a blade that was twenty-four inches long, sharp on both edges, and pointed at the end. The Word of God is living and sharper than the two-edged sword of the Roman soldier.
When Jesus was tempted in the wilderness in Luke 4, He gave verses of Scripture to Satan to resist his temptations. There is no greater example from whom we can learn than Jesus. He would quote out loud the verses of Scripture each time Satan attacked Him in the wilderness.
I believe this is how we are to resist the devil. Take God’s promises, speak the Word of God and the promises of God, and use the Word like a sword.
Satan attacks us on a daily basis. Therefore we need to check our armor daily and make sure it is polished, oiled, and ready for active duty at all times. Don’t allow your sword to get rusty by not studying the Word. Keep it sharp—study and know the Word—to defeat the enemy.