Based on verses such as 1 Thess 5:23, I believe that the human person is “tripartite”—that is, we are spirit, soul, and body.
Hebrews 4:12 is another verse that supports the tripartite view. It also suggests an important clue about the role of the spirit in the human person:
For the word of God is living and powerful, and sharper than any two-edged sword, piercing even to the division of soul and spirit, and of joints and marrow, and is a discerner of the thoughts and intents of the heart (Heb 4:12).
Notice how the passage mentions both soul and spirit. And while it doesn’t explicitly mention the body, it is implied by the references to joints and marrow.
Hebrews compares soul and spirit to joints and marrow. The mention of marrow caught Major Ian Thomas’s attention. He initially studied to be a missionary doctor and knew something about the importance of the marrow.
Marrow is the nutrient-rich spongy tissue at the center of large bones. Among other functions, the marrow produces blood cells. As Thomas noted,
It is a physiological fact that the blood is manufactured in the marrow, and this “source of life,” being of such paramount importance to the body as a whole, is buried and protected deep within the joints and the bones (Thomas, Mystery of Godliness, 62).
The marrow manufactures blood. That is highly significant for Thomas because of what blood symbolizes. Throughout the Bible, blood was sacred. You could not eat it (Gen 9:4; Lev 7:26; 17:10; 19:26) or shed it (Gen 9:6) because blood was life (Deut 12:23), and life belongs to God.
For Thomas, understanding the meaning of marrow and blood is the key to understanding the passage in Hebrews:
[T]he blood is sacred in the Bible. It represents the very life of God Himself—the Spirit of God within the human spirit, as the blood flowing through and from the marrow, imparting the very Life of God to the human spirit, from whence this Life must flow to activate the ‘joints’ within the human soul, and produce that pattern of behavior which enables man to bear the image of the Invisible, and give expression to the Indwelling, Quickening, Motivating Life of God (Thomas, Mystery of Godliness, p. 62).
Just as you need marrow to produce blood to give physical life to your body, so, too, you need the Holy Spirit to give life to your human spirit, and through it, to give life to your whole person (cf. Rom 8:11).
