Matthew 13:31-32 - He told them another parable: “The kingdom of God is like a mustard seed, which a man took and planted in his field. Though it is the smallest of all your seeds, yet when it grows, it is the largest of garden plants and becomes a tree, so that the birds of the air come and perch in its branches.”
This chapter has Jesus describing the kingdom of God in a variety of different ways. This particular example paints a picture of how easy it is to spread the kingdom. Jesus tells us that the kingdom of God is like a mustard seed that is planted in the ground.
A mustard seed is not much in itself. It is very small and only becomes useful when you plant it. What I believe Jesus is trying to say here is not that God’s kingdom is very small, but that it doesn't take much to spread it. All you need to do is plant a small seed.
This seed doesn't have to be much, maybe something you say, or possibly something you do. A small action and the seed is planted. Then God makes it grow.
In this picture we see that even though the smallest seed is planted, God grows it into a tree. That is what He will do for you as well. God won’t make something grow that is not there, but once we plant the seed He takes over. He has given us the responsibility to plant the seeds.
When Jesus taught us to pray He told us to pray that God’s ‘kingdom come, on earth as it is in heaven.’ Well this is how it comes. You are the key.
God wants to bring His kingdom to earth through you and it only takes a small seed at a time. So be an example, throw some seed and trust God to grow it in the lives of those around you.