The parables explain to us how the kingdom grows. The gardener does the hard work, but it is a wonderful mystery how plants grow. Jesus is coming to gather in His harvest. God is sowing His seed and we don't need to worry that there won't be a crop for Him. It is a surprise that such a small seed could grow into such a large tree. A Christian in the Roman empire might have thought the church would soon be snuffed out. Throughout the ages we have seen the church grow.