The 20/80 Rule and the Underwear Corollary

We had a great discussion today in our last Gospel Narratives class for the semester about how to put together all of the methods we have learned into a coherent whole. One of the issues which came up in that discussion was the length of time this process would take, which can seem out of proportion to the public communication of the material in a teaching context. In talking this through, my colleague in the class, Darrell Bock, stated his 20/80 rule. Here it is, paraphrased somewhat:

You only preach or teach about 20% of what you discover in your study and exegesis. However, the quality of the 20% you use is directly related and supported by the 80% you leave behind.

The practical application for exegetes is that you cannot study just to teach that 20% because in reality you'll then misunderstand it. Communication of biblical truth is always a small subset of everything that  goes into understanding a passage. The 80% that doesn't see the light of day has to be there in order for the 20% which does to be properly understood.

To this I like to add what I have termed the Underwear Corollary. This is not original with me. In my circles a form of this is attributed to Dr. Haddon Robinson, who said something to this effect: "When you preach, Greek and Hebrew should be like your underwear: always there, but never shown publicly." For the purposes of understanding exegetical method, I'd like to rephrase and repurpose this into the Underwear Corollary:

Certain parts of the exegetical method are like your underwear: You've got to put them on first in order to be well-dressed, but they aren't what you show when you teach Scripture publicly.

The point is largely the same: The exegetical method is designed to give breadth to our understanding of Scripture. If we short cut the process, we ultimately cut short our communication of its truth.