Matthew 13 contains several parables about the kingdom of heaven. Two of these parables—the mustard seed and the leaven—make the same basic point about the growth of the kingdom but with slightly different shades of meaning. Both challenge our preconceptions about the way the kingdom should work.

1. The mustard seed. “The kingdom of heaven is like a grain of mustard seed that a man took and sowed in his field. It is the smallest of all seeds, but when it has grown it is larger than all the garden plants and becomes a tree, so that the birds of the air come and make nests in its branches” (Matt. 13:31-32).

Mustard was the smallest seed commonly planted in the gardens of Judea. It was so small that you could barely see it, yet it grew to an impressive size of ten to twelve feet tall. In its mature state, the mustard tree was able to be climbed and provided a home for birds’ nests. You would never expect that such a tiny seed could amount to so much!

The insignificance of the church’s origins is astounding. The kingdom of God did not come to the earth with great political machinations or the support of kings and war heroes. It was not bankrolled or advanced by the wealthy and powerful. This is what the Jews expected would happen when the kingdom was established. Most believed that the Messiah would come and lead Israel to glory, mobilizing the crowds as the ultimate king and commander. In their minds, this would be impossible to miss and would dramatically change the world.

In reality, after Jesus ascended back into heaven, there were only a few believers left who waited for the coming of the Holy Spirit (Acts 1:15 mentions 120 people who gathered with the apostles). On the day of Pentecost, it was Peter and the other apostles who preached the gospel message—and they were ordinary people of little power! The beginning of the kingdom was not even noticed by everyone in Jerusalem, much less Judea or the world. Some who did witness it didn’t realize what they had seen.

Despite this, the kingdom of God did not fizzle and die. It grew dramatically and spread throughout the world in rapid fashion, able to bring lifegiving sustenance to people far beyond where it originally germinated.

2. The leaven. “The kingdom of heaven is like leaven that a woman took and hid in three measures of flour, till it was all leavened” (Matt. 13:33).

Leaven is a raising agent used in baking bread. If you’ve ever forgotten yeast in your bread dough, you know how necessary that little pinch is! The kingdom of God is like that pinch of leaven mixed into a large portion of flour. The yeast’s effect is not localized or minor—it causes the dough to expand in every direction.

If my wife mixes a batch of dough and calls me over to come look at it, I have no way of knowing if she included the yeast or not. It would be obvious if she forgot the flour or the water, but the yeast is hidden. Even if I know the leavening agent is there, I can’t see the expansion of the dough in real time. It happens too slowly to notice at any given moment. Yet, there is no mistaking the effect of the yeast in the dough as it rises and bakes. The finished loaf of bread has been unquestionably and radically changed by the presence of the leaven.

The growth of the kingdom of God is not always easy for us to see. There’s very little about its origins that would make a historian expect it to grow, yet it grows all over the world through the working of the Spirit in the hearts of men and women.

3. Don’t be too pessimistic about the kingdom. It is true that only a minority of people will come to Jesus (Matt. 7:13-14), but this should not make us sound the death knell for the church. I think that some Christians are so downtrodden that they hope they don’t find themselves alone in heaven when the judgment comes! The growth of the kingdom defies conventional understanding, but it still grows today. God’s word will not return to Him empty (Is. 55:11). There are still people today who are seeking fellowship with God and forgiveness for their sins who respond with joy and obedience when they hear the truth.

Instead of bemoaning the secular and wicked nature of society, we must “work while it is day” (John 9:4) to tell the good news so more can be saved from their sins. Praise be to God for the growth of His kingdom!