dDavidfromNC makes a good observation is noting that the terms soul and spirit are oftimes used interchangeably. As with all lexical concerns, context is key.
Hbr 4:12 For the word of God [is] quick, and powerful, and sharper than any twoedged sword, piercing even to the dividing asunder of soul and spirit, and of the joints and marrow, and [is] a discerner of the thoughts and intents of the heart.
What does this mean?