"In all circumstances take up the shield of faith, with which you can extinguish all the flaming darts of the evil one; and take the helmet of salvation, and the sword of the Spirit, which is the word of God..." (Ephesians 6:16, 17)
Think of "the sword of the Spirit," the word of God, as the sword the Spirit both wields and gives us to wield. The Holy Spirit wields the word of Christ; it is how he works, and what he came to do. In John 15, Jesus said of the Spirit, "He will take what is Mine and declare it to you." The Spirit takes Christ's word, the Scripture, and puts it into our hands as we study it, meditate on it, and abide in it; he makes it our weapon of righteousness. We are to take it up and when we do, in the power of the Spirit, he takes our hand and guides the strokes, slashing here, exposing there, as the sword does its living work.
"For the word of God is living and active, sharper than any two-edged sword, piercing to the division of soul and of spirit, of joints and of marrow, and discerning the thoughts and intentions of the heart"(Hebrews 4:12).