"Take … the sword [machaira] of the Spirit, which is the word of God." (Ephesians 6:17b NIV)
The Greek word translated sword in Ephesians 6:17 is machaira—a sword of judgment. This is not a combat, battle sword used to slay earthly enemies in a fight but rather a sword used in executing judgment. This is because our first priority is not to condemn any person, Christian or not, but rather to point them to the resurrected Christ and the Word of God—where they ought to be judged. Therefore, if there is any judging to be done on this side of the return of Christ, we let the sword of the spirit, which is the Word of God, do the all the judicial work.
You see, our combat as Christians is not against human foes because flesh-and-blood enemies are tools of Satan’s realm. The real enemy that lurks behind our supposed human foes is Satan himself—and technically, this whole war has already been won, captivity taken captive and gifts given unto man. In this day and time we do not need a battle sword for combat, we simply need the word of truth, the machaira sword, the sword of justice wielded figuratively for judicial punishment. We wield this machaira sword against principalities and powers by living, speaking, and being the Word of God.