Commentaries are not inspired. This should be a no-brainer, but it’s still something I have to remind myself of.
I’ve been particularly frustrated lately with a study I’ve been doing on Bathsheba (hopefully I’ll be able to post something later). The liberties some authors take with their speculations can be really be annoying. If it’s not spelled out pretty plainly in the text—or somewhere else in the Scriptures, then it’s conjecture. I don't have a problem with using a sanctified imagination, but I think it should be made clear when that's being done. I’m surprised by how many “speculations” in Scripture I’ve taken for fact only to discover they were someone’s fanciful idea of how it might have been.
For instance, we had a funny go-around in our home Bible study recently about whether the Bible says the Old Testament priests tied a rope around the ankle of the priest who went into the Holy of Holies. That way if he died in there he could be safely pulled out without exterminating the other priests. Some of us were just sure it was written somewhere. But no, it’s just a legend that began in the Middle Ages. (see HERE)
I think it’s wise for Bible students to consult a number of reliable resources such as word studies, Bible dictionaries, and commentaries when studying a passage, a book, or a subject in Scripture.
I don’t believe we should come to the Scriptures in a cavalier manner thinking we can correctly dissect a passage using only an inductive type of study method that never cross-references or uses any type of outside reference. (Think about the fact the God gave the church pastors and teachers for a reason.)
One of the rules of hermeneutics (which is just a fancy word that means the art and science of interpreting Scripture) is that Scripture interprets Scripture. The Bible passages we study need to be read and understood not only in their immediate context but in the context of the book it’s in, and also in the entire Bible. Other things need to be considered as well, such as who wrote it, who it was written to, when, where, and the cultural situation, etc. If we don’t do this we can come up with all sorts of crazy teachings—but that’s a blog for another day.
When I’m studying a particular book, passage, or subject I normally try to read at least a half dozen commentaries on that passage—more if I can. But the commentaries don’t always agree with each other even when they’re from the same theological perspective. While they all bring something a little different to the table, they can have radically different takes on a passage or subject
So, the bottom line here is that it’s good to read a number of opinions on a matter. And while there are many non-negotiable doctrines in Scripture, there can still be a wide variety of speculation on certain passages.
As we put forth the effort to study the Scriptures the Holy Spirit will help us to understand them because it is the Scriptures that are inspired not the commentaries.
Related studies from here:
Bibliology: How We Got Our Bible