Recently I was privileged to be featured on Matthew Ralston's podcast, "Createdverse." We discussed the principle of the "common sense" reading in Hermeneutics. You can watch the interview here.
A common expression about Bible study heard within Christian circles is, "When the plain sense makes common sense, seek no other sense" (the earliest use of this phrase that I have found is David L. Cooper, What Men Must Believe [Los Angeles, CA: Biblical Research Society, 1943], 63; please let me know if you find an earlier reference!). While this expression does not solve all hermeneutical issues (after all, sometimes the plain sense does not make common sense), it is perhaps the single most important principle for studying the Bible, and it does not require the average Christian to possess knowledge of Greek or Hebrew, only a good translation.
The application of this principle places the authority of Bible interpretation right where it should be, in the intended meaning of the original author to the original audience, not in the creativity of my brain in its attempt to find a "deeper" meaning. This principle, for example, prohibits us from seeking the identity of the antichrist in texts such as Luke 10:18, as one pastor in Florida did back in 2009 (his implied answer? The antichrist is Barak Obama!). More close to home, the application of this principle strongly discourages us from seeking for a "deeper meaning" in the identity of the seven churches in Revelation, as if they were 7 different eras of history. Yes, Revelation does look to the future, but it also concerns John's present era (Rev 1:19, "Write the things which thou has seen, and the things which are, and the things which shall be hereafter"). In Rev 1:11 Jesus said "write . . . and send it unto to the seven churches which are in Asia," not "to the seven eras throughout history," so we should assume they are literal churches unless there are clues otherwise. (As a side note, we already had a symbol representing the 7 churches, clearly explained, in v. 20; it would be odd if we had a symbol representing another symbol representing something not even remotely related to the text).
To claim the seven churches are seven eras, when we have not yet reached the main apocalyptic-futuristic sections of Revelation yet, suffers from two debilitating weaknesses. First, to identify Laodicea as the modern era (rich, self-sufficient) ignores the poor, persecuted Christians currently suffering in China, India, Nigeria, etc.; it's an overly anglo-centric perspective that seems to assume that North American and European Christians are the only Christians in the world.
Second, such a pseudo-"deeper" meaning beyond the plain NT meaning of "church" removes all restrictions for interpretation other than my own creativity. After all, why couldn't the seven churches represent seven types of Christian music? (One of my former professors actually heard such a view presented at a conference!) Or perhaps 7 different Bible translations? Or 7 different types of coffee shops? Yes, I'm being silly, but that's the point! When you are not content with the plain sense, when the plain sense is sufficient, what is to keep you from being silly?
Anyways, listen to the interview to hear more on this topic of the "plain sense," the single indispensable element (besides the indwelling Holy Spirit) to effective Bible study.