A mortar and pestle used to be standard equipment in kitchens, pharmacies and high school science labs. They could be made of stone, wood or metal, but most often they were ceramic, as in the picture below.

Sixty-five years ago I sat in a high school classroom as our teacher demonstrated how gunpowder was made. He took charcoal, sulphur and saltpetre and used the mortar and pestle to grind them to powder. As he was doing so, he placed his left hand over the top of the mortar to keep it from moving around on his desk, holding the pestle between the thumb and forefinger of that had and using his right hand to move the pestle around to grind and mix those three ingredients.

DO NOT TRY THIS AT HOME!!!

As he was doing that, he continued to talk to us, explaining the history and use of gunpowder. I’m not sure what his plan was for demonstrating the explosive power of gunpowder, but he achieved something much more persuasive than he could have planned. His left hand pretty much sealed the top of the mortar and his manipulation of the pestle cause friction, which produced heat, which led to

Shards of pottery shot across the classroom; students dived for the floor on the side of their desks away from the source of the explosion. The teacher was as startled as the rest of us but quickly gathered his wits and asked if anyone had been hurt. No one had, except I think the palm of his hand must have suffered some burns and scratches. Then he asked one of the students to get a broom and dustpan to clean up the debris.

That was the coolest science experiment ever (but don’t try it at home). It didn’t turn out as the teacher had planned, but we all left school that day with the recipe for gunpowder and the knowledge of its power permanently engraved on our minds.

There is another situation where a man stands in front of a group of people to talk, and power is unleashed. The apostle Paul called it the foolishness of preaching.

For after that in the wisdom of God the world by wisdom knew not God, it pleased God by the foolishness of preaching to save them that believe. 1 Corinthians 1:21

How can saving power be produced by an ordinary guy standing in front of a group of people and talking? Well, first of all, the guy doing the talking is not the source of the power. But as he speaks, he must blend together three essential ingredients: the Word of God, faith and love. Leave any one of them out and there is no power. A man may have a profound and true faith, but without the Word of God his words sound like his own ideas, without love, his words sound like accusations.

It is good to study the Scriptures, the historical setting in which they were written and the original meaning of the words. But that is not an essential ingredient in effective preaching. Taking shortcuts to that learning can lead to pre-packaged distortions of the truth of God’s Word.

Learning to speak clearly and effectively is good, but we need to steer clear of trying to manipulate people’s emotions. The essential ingredients of preaching with power are the Word of God, faith and love. These three work together even in the mouth of those of little learning or speaking skill.

When they are brought together, the Holy Spirit provides the spark that produces an explosion that blows away our pride, our self-righteousness, our hurt feelings, our suspicions and all the other walls we have built that we think are protecting us, but which are really barriers to fellowship with God and with other believers.

To be sure, the explosion is silent and invisible. The results are nonetheless real. Let’s sweep all that rubble onto the rubbish heap rather than trying to use it to rebuild those walls.