I just got asked by a member of our congregation whether we are a body & soul, or a body, soul and spirit? She was aske by her daughter. This is a very brief answer — it is certainly much more complex and entails matters of the relation of the material and immaterial, et cetera. So, remembering the circumstance, here is an answer:
Are human beings made up of body & soul or body, soul & spirit?
This is a very old question in the history of Christianity, and it has been answered both ways by sincere Christians.
We first start with the obvious proposition that human beings are composed of an inner & outer self, that which is material (our body) and that which is immaterial (our mind, if you will). We move about in the physical world; and we have thoughts, hopes, aspirations, memories which are not physical.
Some Christians would hold that we have a body and a soul – both of which we have in common with animals. However, being human, we also have a spirit which sets us above animals. There are a few variations on this thought, but it generally sounds like this. These people will often point to:
23 Now may the God of peace himself sanctify you completely, and may your whole spirit and soul and body be kept blameless at the coming of our Lord Jesus Christ. 1 Thessalonians 5:23 (ESV)
That looks and sounds very convincing. But there are some problems with the argument. First, the Bible usually does not distinguish between one material and two immaterial aspects of human nature. Second, “spirit and soul” can also be understood as just a way of saying “all of you”. Third, the words “spirit” and “soul” are used to describe an aspect of animals. Fourth, the word “soul” (the lesser word” is even used to describe God (Heb. 10:38, “my soul has no pleasure in him”). Fifth, “soul” is used to describe the continuous part of deceased Christians (see, e.g., Heb. 10:39, Rev. 6:9). Sixth, the word “soul” is used to describe the highest exercises of spiritual action (see, e.g. Mark 12:30—which describes a human as having 4 parts! – Luke 1:46, etc.). Seventh, to lose your “soul” is to lose everything (Mark 8:36-37).
This is certainly not everything which can be said about body, soul & spirit. There are complications here which delight philosophers and make everyone else blink in confusion.
So what do you say, body, soul, spirit? As a general rule, it is best to speak of humans as having a material and immaterial aspect, an inner and outer person, a body & soul (but if you say body and spirit, it will be okay).
These are partial parallels to the present terminology, but throw little light on its details: what the writers mean is, “May every part of you be kept entirely without fault.
F. F. Bruce, 1 and 2 Thessalonians, vol. 45, Word Biblical Commentary (Dallas: Word, Incorporated, 1998), 130. Calvin takes the phrase as referring to two aspects of one immaterial aspect:
We must notice, however, this division of the constituent parts of a man; for in some instances a man is said to consist simply of body and soul, and in that case the term soul denotes the immortal spirit, which resides in the body as in a dwelling. As the soul, however, has two principal faculties—the understanding and the will—the Scripture is accustomed in some cases to mention these two things separately, when designing to express the power and nature of the soul ; but in that case the term soul is employed to mean the seat of the affections, so that it is the part that is opposed to the spirit. Hence, when we find mention made here of the term spirit, let us understand it as denoting reason or intelligence, as on the other hand by the term soul, is meant the will and all the affections.
John Calvin, 1 Thessalonians, electronic ed., Calvin’s Commentaries (Albany, OR: Ages Software, 1998), 1 Th 5:23.
 For those who really want extra credit:
It is precarious to try to construct a tripartite doctrine of human nature on the juxtaposition of the three nouns, πνεῦμα, ψυχή and σῶμα. The three together give further emphasis to the completeness of sanctification for which the writers pray, but the three together add but little to the sense of ὑμῶν τὰς καρδίας (“your hearts”) in 3:13. The distinction between the bodily and spiritual aspects of human nature is easily made, but to make a comparable distinction between “spirit” and “soul” is forced. Few would care to distinguish sharply among the four elements “heart” (καρδία), “soul” (ψυχή), “mind” (διάνοια) and “strength” (ἱσχύς) of Mark 12:30 (amplifying the threefold “heart, … soul, and … might” of Deut 6:5). The distinction made by Paul between ψυχή and πνεῦμα in 1 Cor 15:45 has no bearing on the present passage: there the distinction lies between the “living person” (ψυχὴ ζῶσα) which the first Adam became at his creation (Gen 2:7) and the “life-giving spirit” (πνεῦμα ζῳοποιοῦν) which the second Adam has become in resurrection. It is the contrast between the two nouns in that sense that constitutes the contrast between the adjectives ψυχικός and πνευματικός in 1 Cor 15:44, 46 (ψυχικός means χοϊκός as πνευματικός means ἐπουράνιος). The contrast between ψυχικός and πνευματικός in 1 Cor 2:14, 15 depends on the contrast between the soul of man and the Spirit of God; the understanding of the ψυχικὸς ἄνθρωπος is confined to the capacity of “the spirit of man (τὸ πνεῦμα τοῦ ἀνθρώπου) within him” (l Cor 2:11), and without the indwelling Spirit of God he cannot appreciate the πνευματικά, the “things of God” (1 Cor 2:11). In that context πνεῦμα is practically synonymous with νοῦς (cf. 1 Cor 2:16).
Plato speaks of the mind as being in the soul, and the soul in the body (νοῦν μὲν ἐν ψυχῇ, ψυχὴν δὲ ἐν σώματι, Tim. 30B), but for him the νοῦς was part of the ψυχή. Marcus Aurelius distinguishes σῶμα, ψυχή, νοῦς by saying that sensations belong to the body, impulses to the soul and opinions to the mind (σώματος αἰσθήσεις, ψυχῆς ὁρμαί, νοῦ δόγματα, Med. 3.16). MM (s.v. ὁλόκληρος) quote from the third-century magic P Lond 121, line 590, διαφύλασσέ μου τὸ σῶμα τὴν ψυχὴν ὁλόκληρον, “keep my body [and] my soul in sound health.” These are partial parallels to the present terminology, but throw little light on its details: what the writers mean is, “May every part of you be kept entirely without fault.” On the “complexive” aorist optative τηρηθείη cf. what is said on ἀγιάσαι earlier in the verse.
F. F. Bruce, 1 and 2 Thessalonians, vol. 45, Word Biblical Commentary (Dallas: Word, Incorporated, 1998), 130.