One of the verses we talked about is Revelation 1:16 which is part of John's description of Jesus Christ. He ways of Christ: "And in his right hand [he held] seven stars: and out of his mouth went a sharp two edged sword: and his countenance was as the sun shineth in his strength." We talked about how the symbols of the two-edged sword is found in many places in scripture including Doctrine and Covenants 33:1 and Hebrews 4:12 and that when we see all the verses it becomes evident that the two edge sword is a symbol for the word of God.
But why a two edged sword? A two edged sword can inflict damage from both sides of the blade and thus is more powerful, but it also means that if you are striking at an enemy one side of the sword is poised to destroy the enemy but the other side is poised to destroy you. In other words, a two-edged sword offers a good or a bad consequence depending upon how the sword is used.
Thus the word of God is a sharp and powerful thing which if used properly will bring us great joy and will protect us from enemies; but if fought against or not used, it will separate us from God and from the Spirit which gives vitality and life to our being.