Quenton,
You had asked if God's Word can kill...one thing that may be helpful to understand is, a sword in battle is used offensively and defensively. So, bearing that in mind and the Scripture 2 Cor. 10:4, the sword of God's Word (which is Jesus, John 1:1, 14), empowered or enlivened by the Holy Spirit, will destroy or kill the works of the enemy...the strongholds. By doing so, it can bring life to those that are bound and the ability to see through what was holding them back and leading them to death (sin)...how does it do this? (by correcting, reproofing, and instructing on righteousness, 2 Tim. 3:16-17; 2 Peter 1:21). The sword or Word of God will offend the enemy and his cohorts and will defend in righteousness. Therefore making those that are led by His Spirit, or sons of God, victorious in their battles (2 things at one time...2 edged sword...Matt. 10:34-37; Luke 12:51-53; Psalm 149:6; Heb. 4:12).
In regards to Job 41...well, that is the sword or Word of God working at it's best (a perfect example). The Lord was fulfilling exactly what He expects us to do by correcting, reproofing, and instructing Job throughout that chapter...speaking to him of Himself, so that he would understand Who God really is. The Lord was 'stripping' down the whiles of the enemy in Job and enlivening him (his spirit) on understanding the Truth, or God's ways, therefore strengthening him in righteousness and weakening the works of evil in him...bringing him life and dividing the spirit and soulish nature. The Lord was talking about how powerful and mighty He truly is...by just speaking, He is able to do everything (which He described of what He's able to do in that chapter)...comparing Himself to mankind...that they are nothing without Him...they have no power without Him...the power to overcome all things (the enemy and his tactics). In addition, the Lord also was stating that He created the enemy and He was and is more powerful than him and his ways (Job 41:9-11); that if anything, we should fear Him...the One who created all things and is able to destroy all things if He chooses (Matt. 10:28).
You have to also remember that throughout the book of Job, Job was dealing with a lot of others' opinions on how and why God was doing what He was doing to him (dealing a lot with fear, or fear of man specifically), so this chapter was a crucial part of Job's refining...when the Lord made clear to him who he should fear (not man, Psalm 56:4; Heb. 13:6; Psalm 118:6; Rom. 9:20; Isa. 50:2); not the enemy, but God Himself and look to Him as your Help because He will not fail you in the work that He has begun, as long as you continue to believe and trust Him (Luke 8:50; Daniel 10:12; 1 Chron. 28:20).
j_sp