Mold and yeast are first cousins (second cousins to fungi and mushrooms). Both mold and yeast are very primitive microscopic organisms that have found a way of thriving for millions of years. One of their most effective survival strategies is to develop spores (“seeds”) that can be dormant for months, or even years, then come to life in the right situation.

A loaf of bread may have close encounters of the spore kind at the beginning and at the end of its existence. Part of the baking process is the addition of leaven to the dough mixture to make the loaf rise. This may be done by physically adding an agent, usually yeast. But if you just let the raw dough loaf sit for a couple of days, it will start rising on its own. Why? Because there are yeast spores in the air all the time just waiting for the opportunity to dive into a fresh, starchy banquet, where it can feast, multiply, and belch out the CO2 gas which makes the loaf rise. When the rising process has gone far enough, the baker pops the loaf into the oven to prepare it for human consumption.

Most loaves of bread are eaten by hungry people. But once they’ve eaten their fill, part of the loaf of bread may be left on the table for a couple of days, and mold is likely to appear and begin spreading all over the loaf. Where does this mold come from? Right, from spores that have been floating around in the air waiting for their turn.

Spores of yeast, mold and other family members are very abundant in the air we breathe. Though this varies with the location, it has been calculated that the average person inhales about 600,000 spores in an hour – most of these are exhaled with the next breath; those few that attach to the lung walls are usually dealt with by the body’s immune system. Some spores may contribute to allergic reactions, and a few can cause diseases, but most are harmless to us. Humans have coexisted with yeast and mold spores throughout their history as a species.

Jesus told this parable to a group of potential followers: “The kingdom of heaven is like yeast that a woman took and mixed in with three measures of flour until all of it was leavened.” (Matthew 13:33)

He was calling attention to something they could observe any day in their kitchens — the mysterious power of yeast to extend its influence rapidly through the whole loaf of bread. He said the Kingdom of God has a similar capability to expand quickly and effectively, without being observed.

But if the woman didn’t add the yeast, just letting nature take its course, the whole loaf would still have become leavened because of the yeast spores in the air. There is much in Jesus’ teaching that indicates he was aware that Holy Spirit Spores were in the atmosphere all around him, ready to bring the powerful realities of the Kingdom of God into the lives of people who were open to spiritual leavening.

Some of the people who heard Jesus closed themselves to his Kingdom invitation. Later, they wondered where the mold in their lives came from. Other spores.

— Pastor George Van Alstine