Nope, Hebrews 4:12 doesn't say it divides between spirit and soul, it says,
"For the word of God is living and active, sharper than any two-edged sword, piercing to the division of soul and of spirit, of joints and of marrow, and discerning the thoughts and intentions of the heart."
It's not cutting between soul and spirit, it cuts through both, through joints and marrow. That is, it pierces right to the center.
And mention of the word "spirit" does not mean there is a human spirit distinct from a human soul. Both speak of the life of a person (as does the body). Since man is a physical creature, a rational creature, a worshiping creature, a moral creature.
I don't have something called a "spirit" nor do I have something called a "soul". I am both of these things, just as I am my body, and I am my mind, and I am my consciousness, and all my emotions, feelings, experiences, sensations, and memories are all me.
-CryptoLutheran