Trains, well more so, their tracks have always fascinated me. How an engine weighing tons and sometimes pulling tons and tons of cars behind it can travel on two parallel strips of very smooth steel is fascinating.
The train travels on a "gauge" - a 4-foot, eight-and-a-half inch width - which is the standard in the U.S. at least for most of its history. But what keeps the train traveling on its predetermined route is the inner lip on the train's drive wheels that presses equally to both sides of the two rails. And as long as that balance remains the train stays "on track."
Balance between two extremes is what keeps the train true even in curves and hills and descents...
So it is with preaching and the work of the gospel.... if one rails looses "gauge" there is shipwreck (or train wreck) ... doesn't matter which side looses gauge..... the result is the same. Wreck. Going left or right in safety, for the train, is when both rails maintain the gauge.
Balance is the first rule -- and the second and the third.
Every situation we face can be presented from the extremes.... but keeping the Biblical "gauge" in all things is not only good but imperative!