These two parables are part of an entire chapter of parables. So far in the chapter, each parable has taught something about the kingdom of heaven. First there was the famous parable of the Sower; Jesus there declared that the kingdom comes by way of the Word of God taking root in the hearts of believers, growing, and bearing fruit, while there are many other people in whom the Word of God does not bring forth fruit (vv. 1-9). Next there was the parable of the wheat and the tares. There Jesus made clear that the visible kingdom will remain a mixture of good and bad until His return on the clouds and the final separation of the righteous and the wicked (vv. 24-30). There was more for His followers to learn about the kingdom, however, and so Jesus continued His teaching in the parables of the mustard seed and the leaven. Through these two parables Jesus focused His disciples on the remark­able, invisible power revealed in the growth of the kingdom through the gospel. He compared this power to two very familiar things.

It’s like a Mustard Seed⤒🔗

The mustard seed is miniscule, about the size of the tip of a pencil lead. Your eye would scarcely notice it. Were a mustard seed to fall on you, you might not even take the effort to brush it off – it’s that small. A bird looking for seeds to eat might miss this tiny seed and move on to something larger, such as a sunflower seed. Nevertheless, if this mustard seed falls into the soil and if rain and sun nurture it, a month or two later you could see a remarkable bush that has grown from that very small seed. How is that possible? When it was a seed, it looked like nothing. It seemed worthless and lifeless. But after it has nestled in the soil and received sun and water, the bird that didn’t notice it before might soon find this bush a good place to build its nest.

Likewise, the kingdom of God may look insignificant, worthless, and lifeless to us. We might be tempted to pass over it in our thinking and instead dwell on things seemingly more substantial and eye-catching – things like earthly governments, the media, popular trends, political figures, human institutions, and so on.

The same would have been true of the kingdom of God in Christ’s time. If you had lived then, perhaps your atten­tion would have been focused on the Roman government as it controlled the then-known world. Uprisings, taxes, political intrigue – many such things would have seemed a lot more significant than a wandering rabbi from the back country of Galilee with a band of twelve followers. Like Nathanael, many would have said: “Can there come any good thing out of Nazareth?” (John 1:46).

How many throughout the Roman Empire do you think noticed what happened one Passover outside of Jerusalem, when Jesus was crucified between two thieves, with all His followers scattered and offended? Don’t you think what happened there seemed like just a little dark mustard seed compared to things that must have seemed more important? What significant change could be expected to come out of a tomb in a garden just outside Jerusalem? What lasting good could come out of Galilean fishermen spreading the news about things they saw and heard?

Yet, when we survey the growth of God’s kingdom since Christ’s death, what a gigantic “bush” has grown up! And it continues to spread, over lands and nations, across oceans and deserts. People from every corner of the earth have seen this “bush” branch out right in front of them, and, like birds, many have found a place to hide and shelter among its branch­es – all from a single, miniscule “mustard seed” planted in the soil outside of Jerusalem long ago.

But Christ wants to teach another aspect of the kingdom of God and its growth. He goes on to use another familiar picture.

It’s like Leaven←⤒🔗

Leaven or yeast is a fermenting fungus. What Jesus refers to would have been a piece of fermented dough from a previ­ous baking, which a woman would knead into a new batch of dough. Imperceptibly, the leaven would move throughout the whole dough, powerfully impacting all of it and making it rise.

Sometimes the Bible uses the picture of leaven for some­thing evil, such as “the leaven of the Pharisees” (Luke 12:1) or “the leaven of malice and wickedness” (1 Cor. 5:8). Evil can indeed move imperceptibly and powerfully. However, in this passage, Jesus is not referring to something evil; He is again referring to the kingdom of heaven and its growth within individuals throughout the world. So how does the kingdom of heaven work like leaven?

1. Its work is hidden from view. The process of leavening cannot be seen with the human eye. Neither can the growth of the kingdom of God in a person’s heart. The Spirit changes a heart of stone into a heart of flesh. This new heart is soft and pliable. Although the effects of His work will indeed become visible, this radical transforma­tion is in itself mysterious and invisible.
    
2. It changes from the inside out. Jesus accused the Phari­sees of cleaning only the outside of their “cup,” while the inside remained dirty (Luke 11:39). Their lives might have seemed righteous on the outside, but their hearts remained unclean and evil. This is not how the kingdom of God works in the heart. Like leaven working from the inside out, the changed heart brings forth a changed life (Prov. 4:26).
    
3. It works a comprehensive change in the end. Leaven makes the whole loaf rise. It makes it light and airy and tasty throughout; not one bit of loaf is left unaffected. Like­wise, someone whose heart has been affected by the gos­pel will ultimately show in his whole life that a change has taken place. It’s true that, on this side of eternity, the believer will still continue to be plagued by sin, since there are still two principles at work in his life. Yet, the growth of the kingdom within him will impact all of him: his thoughts, his habits, his actions, his words, his pursuits, his priorities – in short, his life as a whole will be dramatically changed.

Applications←⤒🔗

1. Let’s not despise the day of small things. The kingdom of Christ will have its course. It doesn’t come with an outward show, but with an inward power. We would do well to remember this principle as we long to see fruits of the Spirit’s work in our children or in those around us with whom we have been sharing the gospel. Just because we don’t see anything happening on the surface doesn’t necessarily mean that nothing is going on below the sur­face. Let’s continue to pray earnestly that the Spirit of God would do His mysterious invisible work. If He will, then fruits of that work will become visible in time.
    
2. Let’s adore the secret work of God. The Spirit’s work in each heart is mysterious and powerful. It reaches where no one can reach. In the secret depths of sinful hearts, God implants a new principle that radically changes peo­ple in every possible way. The growth of God’s kingdom in hearts affects people of all sorts of backgrounds and situations. Even the most hardened sinners like Saul of Tarsus are no match for this powerful secret work of God. Has this change been worked deep in the recesses of our hearts? Do our lives pass on the leaven of the gospel in our families, churches, workplaces, and communities?

Study Questions←⤒🔗

1. Review what the kingdom of heaven is. Is it the same as the church? Why is Jesus teaching about the kingdom in parables?
    
2. Give an example from church history or your own personal life of how a small or insignificant event grew to be something spiritually significant in the kingdom of heaven.
    
3. What lessons do these two parables give us regard­ing the importance of faith, as well as the power of unbelief?
    
4. Matthew 17:20 refers to faith the size of a mustard seed. Describe this faith. What similarities are there to the seed in this chapter?
    
5. Leaven works by mixture. Apply this principle to the means of grace for ourselves, as well as evangelism to others. How does this relate to being in the world, and yet not of it?
    
6. It has been said: “Don’t judge your day from how much harvest you reap, but how many seeds you sow” Apply these parables practically to your family or calling in life.