The mustard seed and yeast (Lk 13:18-21)

Do you ever get discouraged by the condition of the church in this country? I know I do! In the UK and across most of the Western world, church attendances have been falling for many years, the average age of congregations has been getting older and older. As we look at the contemporary Church of England, it is very easy to conclude that it is marginalised, ineffectual and insignificant.

Now, I don’t know what the future holds for the CofE – there are a number of worrying signs.

But what I do know is that Christ’s Church as a whole continues to grow and will never die. I do know that the Christian faith, the message of the Gospel, will continue to win converts until the very end of the age. Until the day Christ returns, people of every nation will continue to put their trust in him as their Saviour, Lord and King. His Kingdom will continue to expand to embrace a great multitude from every tribe and tongue.

How do I know this, you may ask? Because of the message of Jesus’ two short parables today. Parables in which a man sows a mustard seed and a woman uses some yeast. Taken together, these two parables teach us that Christ’s Kingdom will continue to grow, and that this growth will be invisible but inexorable. Let’s look at both in turn…

  1. The Mustard Seed: The Kingdom will continue to grow globally

The parable of the mustard seed is so short, I might as well re-read it in full. Jesus said ““What is the kingdom of God like? What shall I compare it to? It is like a mustard seed, which a man took and planted in his garden. It grew and became a tree, and the birds perched in its branches.”

This is a parable about extraordinary growth. A tiny mustard seed becomes not a shrub or a large bush but a big tree. A tree so large that birds could sit in it. Something incredibly tiny became home to a huge number of birds.

Jesus wants us to know that the Kingdom of God is just the same. From the preaching of Jesus and his tiny band of disciples has grown a church that is many millions strong and two millennia in age. Remarkably, the church has grown well beyond its original Jewish origins. It has expanded well beyond the historic frontiers of Israel. People of every nation have entered its embrace.

That is the significance of the birds in this passage. Several Old Testament passages, like Psalm 104, Ezekiel 17 and Daniel chapter 4 compare the birds of the air to the nations of the world. Membership of the Kingdom of God is not confined to one nation – it is a truly global phenomenon. Gentiles like you and me are invited to enter it. As I hope we know well, repentance and faith in Christ are the only qualifications necessary for citizenship of the kingdom.

  1. The Yeast: The Kingdom will grow invisibly but inexorably

So God’s kingdom will grow globally. But that growth will be largely unseen by the watching world. It doesn’t grow with a great fanfare or via an expensive PR campaign. It grows invisibly but inexorably as individuals put their faith in Jesus as their king. That, in summary, is the message of the parable of the yeast.

Again, let me re-read it in full. Jesus said: “What shall I compare the kingdom of God to? It is like yeast that a woman took and mixed into about sixty pounds of flour until it worked all through the dough.”

The woman in this parable is clearly preparing to feed a lot of hungry people. She is using sixty pounds of flour (equivalent to 30 kilograms) to make her dough. That should produce enough bread to feed about a 100 people. But her dough will only rise once she has added her yeast. The yeast is tiny and hard to see, but percolates throughout the flour and has a transformative effect.

The same is true of the Gospel message. As the good news of Jesus is passed from person to person it won’t make the news headlines or attract much outside attention. But it is the mechanism used by God to make new Christians and grow his kingdom.

Even as I speak, the message of the Gospel continues to percolate around the world, travelling from one person to another until it reaches the ends of the earth. With the help of the Holy Spirit, even wars, famines and climate change cannot halt its inexorable advance – thank God!


So as I finish, the message of today’s parables is that Christ’s kingdom continues to grow globally. This growth is sometimes hard to discern, but by God’s grace it is inevitable and inexorable. Until the day Jesus returns, he will keep on drawing men, women and children from across the world to faith in him. When we see the church gathered together in heaven, we will see a great multitude that no one could count, gathered from every nation, tribe and tongue.

This means two things for us today:

  • Firstly, don’t despair! Despite all the discouragements we might see in our society and our denomination, God hasn’t given up on his church. People are still coming to Christ even in England, and across the world thousands of come to faith each day. We are witnessing explosive growth in China, for example. Even the Anglican church is thriving in Africa and other parts of the Global South.
  • Secondly, let the message of these parables be an encouragement for us to share our faith in Christ. Whenever we speak to a family member, friend or neighbour about Jesus we are sowing a seed in their lives, we are adding a drop of God’s yeast into their hearts and minds.

Don’t under-estimate the transformational effect that our articulation of the Gospel can have on an individual’s life. Don’t under-estimate the effect that the witness a single Christian believer can have on their whole community – just like a speck of yeast can transform plain flour into a lovely loaf!