Aren't Bible books all separate?

Question: Isn't each book of the Bible to be interpreted in it's own way since they were written separately, at different times, and by different writers?

Answer: Your question is true — sort of — because some of the books are written to stand alone as a letter to a specific group or place, yet God in His sovereignty and foreknowledge provided each book as part of the greater whole. Therefore each individual book cannot be accepted and interpreted as any less than part of a complete picture. This principle of Bible Interpretation is often expressed as "Scripture Interprets Scripture." Even the church recepients of given letters (ie. Corinthians, Galatians) could not fully understand their letter apart from Biblical revelation given to them earlier.

Another term for this is "progressive revelation" — the idea that God revealed more on subjects over time. For example, though Old Testament writers knew of God's grace, the Messiah, and salvation by faith, these subjects are not revealed in their fullness until the New Testament. In the same way, the O.T. shadows and symbolisms of the law cannot be fully understood until the revelation of the N.T.

Even within New Testament books we need to use one to interpret another. For example, when John uses the term "overcomes" multiple times in the book of Revelation, he never explicitly defines who it is that overcomes, yet another of his letters (1 John 5:4-5) clearly does! The Bible is a complete book. Taking one component book apart from the others is the same as taking one or a few verses from the middle of any one of the component books... It may or may not convey the substance of the whole, or in other words, it may be out of context.

The idea that each book is completely separate from the others comes from a misguided belief that these are merely books written in different times by different people, ignoring the supernatural origin and content of the whole. Remember, God [the author] is not affected by time and space as we are!