For the word of God is living, and active, and sharper than any two-edged sword, and piercing even to the dividing of soul and spirit, of both joints and marrow, and quick to discern the thoughts and intents of the heart.Hebrews 4:12 ASV
That the word of God is “living” is corroborated by other New Testament writers such as Luke (Acts 7:38), Peter (1 Peter 1:23), and others. The word “active” shows that the word does not lie inert and dead but at all times carries within itself the mighty power of its divine author.
Rather than trying to find subtle differences in the meaning of such words as “soul” and “spirit,” it is perhaps just as well to view this verse as a heaping together of powerful terms for the purpose of showing the utmost ability of the word of God to penetrate the complex inward nature of man, to convict him of sin, to expose his hidden motives, and to judge the very nature of life itself.
This verse is a rhetorical accumulation of terms to express the whole mental nature of man on all sides.