During my college years—in my infinite wisdom—it occurred to me that it made no sense to stop at red traffic lights when there was clearly no traffic around. So I began to stop only briefly—just long enough to check for cars—and then proceed. My stops became shorter and shorter, and eventually I no longer stopped at all. I simply checked out the landscape well in advance and—if no cars were coming—proceeded full speed through the red light.

One day something changed all of that, and I've never run a red light since. I was approaching an isolated light in an area where there was rarely traffic in the busiest of times. I had already checked out the landscape and was near the empty intersection when a car topped the hill to my left. It was too far away to pose any threat, but it did pose a problem: it was a police car. But that is not what changed my ways, because I got the car stopped and received no more punishment than a dirty glance.

What scared me enough to put an end to that practice was what occurred in the split seconds between spotting the patrol car and getting the car stopped. In that instant, my foot moved from the gas pedal to the brake pedal, and then back to the gas pedal! I did not will it to do that; my foot just did it. My foot did that because that is how I had trained my mind to respond. I had continually ignored what had once been a clear signal to stop—a red light—and as a result that signal was no longer clear.

The same occurs with sin. Our God-given conscience gives us warning signals, and we can heed those signals or ignore them. If we ignore them often enough, we may eventually fail to recognize them as signals at all.