I’m confused about the difference between the soul and the spirit. Do we have both of these things? What is the difference between them? In 1 Thess. 5:23 Paul talks about our spirit and soul as if they are different, and in Heb. 4:12 we read about the division of soul and spirit, which sounds like they can be divided from one another. Can they be? This is really a difficult question to answer, because different biblical authors use the terms "soul" and "spirit" differently, and no one is ever interested in explaining the components of personhood. In the Old Testament especially, people are viewed as wholes (body/spirit), so to further break down the spiritual essence of people is never a goal of scripture. But all this said, let me emphasize why I think it is unwise (and bad biblical methodology) to develop a theology or even make an argument that we have souls and spirits as two separate elements within us.
The term "soul" is used in numerous ways in the Bible. In Gen. 35:18, it is the principle of life; in Lev. 26:11, it is the soul of God, apparently equal to His mind/will; in Psalm 42 it is the inner person, including emotions and desires; in Matt. 10:28 it is the inner person; in Matt. 26:38 it is the inner person, as in Acts 4:32 where it is paralleled with "heart."
The term "spirit" is used in numerous ways in the Bible also. In Genesis 41 it is the mind or emotions; in 1 Chron. 5:26 it is the seat of the emotions; in Psalm 51 it is the mind or heart; in Matt. 27:50 and Luke 8 it is the inner person/life principle; in Eph. 4:23 it is in a descriptive phrase which equates to "mind." Please note that a definition of "spirit" based on a thorough examination of scripture will not be significantly different than "soul." Each refers to the inner person in its many different aspects.
The parallelisms in these verses, along with the descriptions of the terms already given, demonstrate that no clear distinction can be made between soul and spirit. This view, that the immaterial part of a person is one substance, is known as dichotomy (i.e., we have two components—one spiritual and one material).
A popular view is that we are made up of three parts (trichotomy), not two. We have two immaterial components—both a soul and a spirit. Usually, these are given different meanings (e.g., "spirit" is our life-principle, and "soul" is the part of a person that relates to God). As seen in the previous discussion, however, these distinctions are not maintained by a comprehensive examination of Scripture. The only verses which seem to support trichotomy are 1 Thess. 5:23 and Heb. 4:12. Read 1 Thess. 5:23, and then apply some hermeneutical principles to it. Is Paul interested in defining the way humans are made up in this context? What is his real concern? If he’s not interested in defining personhood here, and could be using an imprecise expression which connotes wholeness, maybe it would be unwise to take this one verse and make a whole theology out of it—especially when Paul elsewhere uses the terms "spirit" and "soul" interchangeably.
Hebrews 4:12 is considered a secondary support for trichotomy, since the author of Hebrews talks about the "division" of soul and spirit, and this is interpreted to mean that soul and spirit are different things. Read this verse also, and ask some hermeneutical questions of it. Is the language used here literal or figurative? What is the author’s real point? If it’s a poetic and figurative passage, is it wise to build a doctrine out of the language?
Consider the use of balanced terms throughout the verse: living/active, soul/spirit, joints/marrow, thoughts/intentions. Note that these are not meant to be strict opposites in all the other cases; in fact, these are collections of synonyms, used in parallel for poetic emphasis. Also I would point out that the "division" of soul and spirit does not mean they are divided one from another. It means that our lives are penetrated (divided, opened up) by God’s word to the depth of our spiritual selves.