The Word of God is the sword of the Spirit which we are to wield in the spiritual warfare that we are involved in. If we do so, we are trading and thereby faithful (and the inverse is also true)

The disciples, including Peter, were neither sober nor vigilant and were consequently overcame. At one point, Peter wielded a physical sword (the sword of the flesh) and it brought disastrous outcome but the Lord restored him and he exhorts us to be sober and vigilant because the devil, our adversary, walks about like a roaring lion looking for someone to devour-1 Pet. 5:8-9.