One of the biggest exegetical fallacies committed by those seeking to support their theological paradigms is that of context replacement. If one needs a word used in a particular text to refer to something other than what it refers to in its context, he must give it another context with new referents. The interpreter will construct a new context for a passage, verse, or word by piecing together other texts of scripture, speculative background material, and his or her own reasoning and then replace the existing context with the reconstructed one. What this practice does is allow the interpreter to make the passage appear to say what he wants it to say, whether supporting his paradigm or simply allowing a passage that contradicts his paradigm in its current context to be consistent with it. Since context determines the meaning of the words used, this has the power of completely changing the text to say something different, and even the exact opposite, of what it originally said.
For instance, if I were to take a simple statement from a reading book, “the cat sat on a hat,” and give it a different context, I can make it say anything I want. I can do this by saying something like, “the word ‘cat’ was often used at the time period this book was made to refer to Sammy Davis Jr. He was ‘the cat’, and often used the phrase in reference to others and himself. The phrase, likely therefore, refers to him. The phrase “to sit on something” often meant to conceal something, as in the phrase, ‘to sit on a story’. The word ‘hat’, of course, often referred to one who played many roles in life, as in the phrase ‘he wore many hats’. This context, then, tells us that this sentence should be understood as, ‘Sammy Davis Jr. concealed the fact that he had diverse talents in life’.
The context, however, existing in pictures in the book, tells us that this is referring to a literal cat sitting on a literal hat. What I must do is ignore that context and replace it with the reconstructed one above. This happens quite a bit with lay interpreters of the Bible. In fact, it is the very reason that massive books, and even series of books, articles, and Youtube videos must be created to convince others of a reconstructed interpretation of a single passage. Pages upon pages, volume upon volume, video after video, consisting of all sorts of “context” from other texts and the interpreter’s own surmising, are created before he ever touches the text at hand. This happens because the interpreter must construct the context he is using from somewhere other than the actual text in front of him if he is to change what the text seems clearly to say in its actual context. Authorial intent is bypassed and the interpreter can now make the text say anything he wants it to say. This is precisely why it is called eisegesis. The interpreter is pouring a context into the text in order to reinterpret it. What he is essentially doing is rewriting the text by supplying another context for it.
This is why people often think the Bible can be used to justify any position. It's not that it actually can be interpreted to support any position from a linguistically responsible standpoint. It's just that, as any piece of literature or any type of speech whatsoever, its context can be ignored and twisted by context replacement. Force someone to stay on the text without reaching for a fabricated context, however, and the many interpretations one can get out of a single text reduce quite drastically.