When we read the Bible, we generally do so looking for instruction. But one difficulty in doing so is that while the Bible has no errors of its own, it accurately records the errors of man. For example, from chapter 4 of Job all the way to chapter 32, we don't see a wise word coming from the mouths of Job's friends. That entire portion describes the folly of three presumptuous men attempting to rebuke their jaded friend, who becomes progressively more angry at them, eventually becoming convinced that God Himself has wronged him. God's response is to first allow Elihu to rebuke Job and his three friends, rebuke Job Himself by displaying His power, then finally, He turns to Job's three friends and demands their repentance for speaking falsehood about Him.
This leaves us with a bit of a problem. If the Bible records such a large portion of error for which God Himself rebuked the original speakers, what exactly do we do with these errors?
The first thing we might be tempted to do is say "well, it's all wrong anyway, might as well just throw it out, or at least ignore it." Slow down a little. This is still scripture, and all scripture is inspired by God, and is useful for doctrine, for reproof, for correction, for instruction in righteousness. In fact, 1 Corinthians 3:19 even goes as far as to say "it is written...", a well known way in which the men of God would refer to authoritative scripture, before quoting the words of Eliphaz, one of the three, in Job 5:13. In other words, as wrong as Job's friends were, even they had some things right. One may even consider them to be lesser prophets; the Lord, through the Holy Spirit, delivered a true message through their lying lips. So what do we do? What can we learn from Job's friends?
The first thing to note about Job's friends is that they weren't completely worthless. Although Job did eventually call them "miserable comforters" because of their accusatory speeches (Job 16:2), their initial response to Job's suffering was good. They came to him in his hour of need, and they did not abandon him. Instead, they mourned with him, they sat quietly with him, they just generally wanted him to know "Job, we love you, you're not alone." And this is a good, Biblical thing to do! The Bible is replete with commands to aid those who suffer (e.g. Galatians 6:2; Romans 12:15; Matthew 25:31-46). Sympathy and empathy are excellent traits displayed by Job's friends, and so their example, in this case, is good.
But God wasn't cross with them because of what they did, but what they said. "You have not spoken of me what is right". This is obviously not 100% true. Eliphaz said "He catches the wise in their own craftiness", and centuries later, Paul said "For it is written, “He catches the wise in their own craftiness”;". So, evidently, not everything Job's three friends said is false. This means that Job's friends gave a toxic mixture of good theology followed by bad theology.
This suggests that the biggest error these men made is extrapolation. They took true facts about God, such as His goodness, and drew a false conclusion. "Job, God is good, therefore you must have sinned, and He must be punishing you." The flip side, of course, being that if you are prospering, it is because God is pleased with you. Tragically, this attitude is extremely popular today in the form of the "Prosperity Gospel".
But to this, God says that suffering is not necessarily due to sin, nor is prosperity due to righteousness. Psalm 73 reveals this very well. Asaph observes the wicked being very prosperous, even to the point of declaring "Surely I have cleansed my heart in vain, And washed my hands in innocence." (v13).
So, how do we deal with the speeches of Job's friends? In a similar manner to Apocryphal books. Apocryphal books have historically been seen as being uninspired, but nevertheless good for devotional purposes. It is entirely permissible to study, and even take inspiration, from apocryphal books. They contain many truths. At the same time, they contain errors. The solution is to filter apocryphal books through the scriptures.
In much the same way, although Job 4-32 are certainly inspired, they still contain accurate records of the errors of Job's three friends, and even Job himself (for which he, too, repented: Job 42:5-6). Thus, every word they speak should also be filtered through the rest of the scriptures. We do not need to disbelieve that God catches the wise in their own craftiness. Eliphaz's conclusion that Job must therefore have been caught in craftiness by God was absolutely wrong. However, his statement that God does this is correct.
To conclude, therefore, we need not panic over what to do with Job's three friends. These are not passages we need to ignore or throw out. Indeed, if God saw fit to include them, it is irresponsible, at best, to do so. At worst, it is sin (Deuteronomy 4:2). Rather, we should learn from these men, copying their good examples and rejecting their errors, of course using the rest of the scriptures to determine what each man did right and what each man did wrong. As the Law, the Prophets, the Gospels, and the Epistles are inspired scripture, so also does Job make the man of God complete, and equip us for every good work (2 Timothy 3:17). Let us therefore treat it as all scripture. Let us study it (1 Timothy 2:15), and write it on our hearts (Proverbs 7:3).