In a Human Context
The soul is the union of body and spirit (Gen 2:7).
Gen 2:7 Then the LORD God formed man of dust from the ground [that’s the body], and breathed into his nostrils the breath of life [that’s the spirit]; and man became a living being [that’s the soul, the union of body and spirit].
At death, this union is broken (Jas 2:26); the body returns to dust (Gen 3:19) while the spirit receives a new body suitable for heaven (1 Cor 15:44). This is since the Second Coming of Christ. Prior to that, the spirit descended below to Sheol (Hades). Thus does Is 14:9 speak of “the spirits of the dead” being there.
I cover a lot of this in the book The Biblical Case for Everyone Going to Heaven but it is not all in one paragraph or even one chapter – so there’s no specific place to point you.
The terms “body” (seen, physical, dust) and “spirit” (unseen, spiritual, cloud) are used more consistently than soul. That is, the word “soul” is sometimes used in different ways. Mostly, it is used as the seat of a human being’s life experience – that is, the place where thoughts and feelings come together (e.g. Ps 23:3); however, it can also be used to describe the whole person (e.g. in Acts 2:41). It is in this latter case that “soul” was sometimes used in the Bible to describe the descent of the spirit at death to Sheol (Hades).
The well-being of the “soul” is a recurring theme in the Psalms as well as the other wisdom literature. This word appears 114 times in the book of Psalms alone. Jesus picks up on this theme and it is prominent in His teaching.
Beyond the Human Context
- God is spirit (Jn 4:24).
- Angels are spirits. (Heb 1:14).
- There the Holy Spirit (Acts 19:2)
- There are evil spirits (Lk 8:1-2)
Other
The word “spirit” also can refer to the way something is done – such as, “…restore such a one in a spirit of gentleness (Gal 6:1) as opposed to always being an entity.