Some believe that it refers to the Church and the Kingdom of God, which in the last days will break all other kingdoms into pieces (Daniel 2:44), therefore apply the verse to individual lives as a prophecy for every believer. Not bad, that word was given to me one morning in 1994, in a meeting of prayer and praise and confirmed the ministerial call to my life.
But being a weapon of war in the hands of God is not automatic. If we speak only of a steel sword it is well, it is useful and it has history. The steel, with much effort, allows the work. But in our case, it is about people (complicated); an object has no senses, emotions, thoughts or will and molding this kind of sword is not easy.
Recently the Holy Spirit turned my gaze to the blacksmith's workshop, the armor-maker for weapons of war; the craftsman who lives in middle of fire and metal; the artist who designs the weapon, chooses the materials and works long hours to produce a weapon that will be faithful in the hands of the warrior. I believe that if we really want to be a useful weapon of war in the hands of God we must analyze how a steel sword is created and draw a parallel with our life.
... Will continue ... meanwhile, access the links to read samples of my books. I look forward to read your comments. God bless you.