Oh that my words were now written! oh that they were printed in a book! Job 19:23.
To understand who wrote the Book of Job we need to examine 28 words that stand out from the others.
Job 32:15 They were amazed, they answered no more: they left off speaking.
Job 32:16 When I had waited, (for they spake not, but stood still, and answered no more;)
Job 32:17 I said,
Who spoke those words? and to whom were they spoken? No one spoke those words. They are not part of the recorded dialog. They are a message interjected into the dialog to tell you the reader how Job and his three friends reacted to Elihu's speech. Take a look at the dialog with those words removed:
Job 32:6 I am young, and ye are very old; wherefore I was afraid, and durst not shew you mine opinion.
Job 32:7 I said, Days should speak, and multitude of years should teach wisdom.
Job 32:8 But there is a spirit in man: and the inspiration of the Almighty giveth them understanding.
Job 32:9 Great men are not always wise: neither do the aged understand judgment.
Job 32:10 Therefore I said, Hearken to me; I also will shew mine opinion.
Job 32:11 Behold, I waited for your words; I gave ear to your reasons, whilst ye searched out what to say.
Job 32:12 Yea, I attended unto you, and, behold, there was none of you that convinced Job, or that answered his words:
Job 32:13 Lest ye should say, We have found out wisdom: God thrusteth him down, not man.
Job 32:14 Now he hath not directed his words against me: neither will I answer him with your speeches.
Job 32:17 I will answer also my part, I also will shew mine opinion.
Job 32:18 For I am full of matter, the spirit within me constraineth me.
Job 32:19 Behold, my belly is as wine which hath no vent; it is ready to burst like new bottles.
Notice that when we cut out verses 15, 16, and a portion of 17, the passage read perfectly. The 28 words that were cut out are not part of his speech to the other men. Elihu paused in his writing to tell you how the men reacted to him.
It is important when studying scripture to distinguish between a passage that is a narrative of events and a passage that is recorded speech. In Job 32:1-19 we have both types of scripture. Verse 15, 16, and the portion of 17 are narrative. They are telling you what was happening. All the rest of the verses are a record of the exact words that Elihu spoke.
Unless Job's three friends and Job himself were to read the book later, they would have never heard those 28 words. Those words are directed at you the reader. When you understand that, there remains no more doubt as to who was the author of the Book of Job.