In the Book of Job, there are nine speaking roles. Job's wife has a one liner, so I will ignore her.
God and Satan speak in the prologue, God as Trinity (Elohim, the strange plural-singular construction, is used as his name) and Satan representing all his minions. Job and his wife also speak in the prologue.
In the main dialogue, there are six speakers: three friends (Eliphaz, Bildad and Zophar), Job, Elihu and the voice from the whirlwind.
Each person in the trinity is represented by a speaker:
- Job is God the Son, the Son of Man (he places his hope in the Son of Man in Job 16:21)
- Elihu is the Holy Spirit (Job 32:8)
- The voice from the whirlwind is God the Father (cares for his creatures)
Each of the three fiends plays an antagonistic role:
- Bildad is the anti-Christ (he insults the Son of Man in Job 25:5-6)
- Eliphaz is the evil spirit (he is visited by a fearful spirit in Job 4:12-17)
- Zophar is the Father of lies (he alone of the friends refers to God as Elohim in Job 20:29)
It is a peculiar asymmetry that Eliphaz and Bildad speak three times, but Zophar only once. Because of the assignments made, consider Zophar coupled with Satan. Then the sequence of Satan and the friends speaking is:
- Satan, Eliphaz, Bildad
- Zophar, Eliphaz, Bildad
- Zophar, Eliphaz, Bildad
Thus the sequence is Father of Lies, Evil Spirit, Anti-Christ.
Looking at the true persons of the trinity, the sequence is:
- Job (Son of Man), Elihu (Holy Spirit), voice of God (Father)
This pattern defines a chiasm (pyramid structure common in Hebrew literature):
A. Father of Lies
B. Evil Spirit
C. Anti-Christ
C'. Son of Man (Christ)
B'. Holy Spirit
A'. God the Father
The assignments of the people to their roles in the Trinity thus has support in the details of their speeches as well as the overall structure of the document.
There are three persons in the Godhead and each has a speaking part in Job. There are three distinct antagonistic roles, and each attacks one person of the Trinity. If there were more persons, there would be more parts.