The Word of God is not simply a collection of words from God, a vehicle for communicating ideas; it is living, life-changing, and dynamic as it works in us. With the incisiveness of a surgeon's knife, God's Word reveals who we are and what we are not. It penetrates the core of our moral and spiritual life. It discerns what is within us, both good and evil. The demands of God's Word require decisions. We must not only listen to the Word; we must also let it shape our life.
The lesson he had just taught from the Old Testament Scriptures was not a mere historical tale. Instead, as had already been made clear by much he had said, it was powerfully relevant to his audience. For the Word of God is living (zōn ) and active (energēs ). Not only that, its penetrating power is greater than any double-edged sword and reaches the innermost being of a person so that it judges the thoughts and attitudes of the heart. In doing this, it is able to discriminate successfully between what is spiritual in man and what is merely “soulish” or natural (it penetrates even to dividing soul and spirit), and does so even when these often-contradictory inner elements are interwoven as closely as joints and marrow. The inner life of a Christian is often a strange mixture of motivations both genuinely spiritual and completely human. It takes a supernaturally discerning agent such as the Word of God to sort these out and to expose what is of the flesh. The readers might think that they were contemplating certain steps out of purely spiritual motivations when, as God's Word could show them, they were acting unfaithfully as did Israel of old.
Resources:
"Life Application Study Bible" by Tyndale House Publishers
"The Bible Knowledge Commentary" by John F. Walvoord and Roy B. Zuck
"The Bible Knowledge Commentary" by John F. Walvoord and Roy B. Zuck